The landscape of third-party cookie deprecation represents one of the most significant transformations in digital advertising history, characterized by years of delays, regulatory intervention, industry pushback, and ultimately a dramatic reversal by Google that has reshaped the entire ecosystem. What began as an ambitious initiative to enhance user privacy has evolved into a complex interplay of competing interests, regulatory scrutiny, and technological innovation, with major implications for how digital advertising, analytics, and user tracking will function in the coming years. As of October 2025, the situation has fundamentally changed once again: Google has officially abandoned its Privacy Sandbox initiative, retired most of the technologies developed as alternatives to third-party cookies, and maintained third-party cookies in Chrome while allowing users to control their preferences through existing browser settings rather than through a dedicated prompt mechanism. This analysis examines the complete timeline of third-party cookie developments, the current state of the ecosystem, regulatory influences, technological alternatives, and what businesses should expect as they navigate this unprecedented shift in digital infrastructure.
The Complex History of Google’s Cookie Deprecation Plans and Multiple Pivots
Google’s journey toward third-party cookie deprecation began with genuine intentions to enhance user privacy, but has been marked by repeated delays, strategic reversals, and fundamental changes in approach that have created significant uncertainty throughout the digital advertising industry. In January 2020, Google announced its groundbreaking intention to phase out third-party cookies in Chrome within a two-year timeframe, representing what many considered a revolutionary commitment to user privacy in the context of web browsing. This announcement came amid growing consumer concerns about online tracking and regulatory pressure from governments worldwide, positioning Google as a privacy advocate even though the company is primarily an advertising business with significant financial incentives tied to user data collection and targeting. However, the company quickly discovered that developing viable alternatives to third-party cookies while maintaining the functionality needed by publishers and advertisers was far more complex than initially anticipated.
The first major delay occurred in June 2021 when Google announced it was pushing back the original deprecation deadline from 2022 to mid-2023, citing the need for more time to develop the Privacy Sandbox initiative and gather industry feedback. This delay signaled that Google had underestimated the technical and business challenges associated with replacing an infrastructure that had been fundamental to digital advertising for three decades. Throughout 2021 and 2022, Google unveiled various components of what it called the Privacy Sandbox, including the Topics API and other technologies designed to provide privacy-preserving alternatives to third-party tracking. Despite these technological efforts, publishers, advertisers, and ad tech companies raised concerns that the proposed alternatives could not adequately support critical functions like brand safety, fraud prevention, frequency capping, and accurate conversion measurement.
By July 2022, Google announced another postponement, extending the timeline to end of 2023, acknowledging that further testing and refinement were necessary. The pattern of delays continued throughout 2023, with additional announcements pushing the deprecation to early 2024, then mid-2024, and eventually to the end of 2024. Each delay corresponded with growing regulatory scrutiny, particularly from the United Kingdom’s Competition and Markets Authority (CMA), which launched an investigation in January 2021 to examine whether Google’s privacy changes might constitute anticompetitive behavior by favoring Google’s own ad tech services over competitors. The CMA’s involvement fundamentally changed the dynamics of the deprecation timeline, transforming what had been positioned as a privacy initiative into a matter of competition law and market fairness.
The most dramatic pivot occurred in July 2024 when Google announced that it would abandon its plan to phase out third-party cookies entirely. Instead, Google stated it would introduce a new user-facing control that would allow Chrome users to make an informed choice about whether to retain or block third-party cookies globally, with that choice applying across all web browsing. This represented a fundamental strategic reversal that shocked the industry, as it suggested that Google had concluded that the benefits of a complete deprecation were outweighed by the technical challenges, regulatory concerns, and business risks. Google’s VP of Privacy Sandbox stated that the company would not deprecate third-party cookies “unilaterally” or force users into a new model without consent, effectively abandoning the core premise of its original 2020 announcement.
However, even this revised approach did not prove durable. In April 2025, Google announced yet another strategic change, this time deciding not to roll out a standalone user-choice prompt for third-party cookies after all. Instead, Google stated it would maintain “the current approach to offering users third-party cookie choice in Chrome,” allowing users to manage their preferences through existing privacy settings rather than through a dedicated browser experience. This announcement suggested that Google had concluded that even opt-in controls might not achieve its privacy goals and that maintaining the status uncon_status while offering technical improvements elsewhere was the most pragmatic path forward. The company emphasized that it would continue to enhance tracking protections in Chrome’s Incognito mode, which already blocks third-party cookies by default, and pursue other privacy initiatives like IP Protection.
The final dramatic development came in October 2025 when Google announced that the Privacy Sandbox initiative itself was essentially dead. The company announced it was retiring ten major Privacy Sandbox technologies, including the Protected Audience API, Attribution Reporting API, Topics API, Related Website Sets, and numerous others that had been developed over nearly six years of work. Google stated that these decisions were made after evaluating ecosystem feedback and observing “low levels of adoption” for most Privacy Sandbox technologies. The company indicated it would only maintain support for a limited set of technologies that had achieved significant adoption: CHIPS (Cookies Having Independent Partitioned State), FedCM (Federated Credential Management API), and Private State Tokens. This announcement effectively signaled that Google’s ambitious effort to create a post-cookie world had failed to gain meaningful traction, and that the company was shifting its focus elsewhere.
Browser-Wide Privacy Initiatives and the Fragmented Landscape of Cookie Blocking
While Google’s approach to third-party cookies has been characterized by delays and reversals, other major browsers took decisive action years earlier, creating a fragmented landscape where significant portions of web traffic already occur in cookie-free environments. Apple Safari introduced Intelligent Tracking Prevention (ITP) in September 2017 with Safari 11, representing the first major browser effort to automatically block third-party cookies and cross-site tracking. Apple’s ITP evolved through multiple iterations, becoming increasingly restrictive toward third-party cookies through regular updates in 2018, 2019, 2020, and beyond. By blocking third-party cookies by default without requiring explicit user action, Apple took a fundamentally different approach than Google’s proposed opt-in model, prioritizing user privacy by default rather than user choice.
Mozilla Firefox launched its Enhanced Tracking Protection (ETP) in September 2019 with Firefox 69, making another major browser unavailable for third-party cookie tracking. Firefox’s ETP blocks third-party tracking cookies by default based on a tracker classification list, with users able to adjust their protection levels from Standard to Strict mode. In Strict mode, Firefox blocks all cross-site cookies, effectively eliminating third-party tracking across the browser. Additionally, Firefox introduced Total Cookie Protection, which creates isolated “cookie jars” for each website, preventing cookies from one site from being used to track users across different sites. This technology fundamentally changed how cookies work in Firefox, making traditional third-party tracking impossible.
Microsoft Edge, based on Chromium but with its own privacy features, offers tracking prevention at multiple levels: Basic (protecting only against malicious trackers), Balanced (the default, blocking trackers from sites the user doesn’t engage with), and Strict (the most restrictive, trading website compatibility for maximum privacy). These browser-level protections mean that in many developed markets, a substantial portion of web traffic already operates without the ability to track users across third-party sites. In the UK, Chrome represents only 49% of browser market share, with all other major browsers automatically blocking third-party cookies by default. In the United States, Chrome’s market share is only marginally stronger at 52%. This means that even before any Chrome deprecation occurs, substantial segments of the digital advertising industry must already function without reliance on third-party cookies in Chrome.
These browser initiatives have created what can be described as a de facto deprecation of third-party cookies, independent of Google’s planned but delayed formal deprecation. Publishers and advertisers have already been forced to adapt to scenarios where a significant percentage of their traffic cannot be tracked using third-party cookies, necessitating alternative approaches even before Chrome’s formal restrictions took effect. The fact that Safari and Firefox reached this state years ago means the industry has had time to develop alternative solutions, test their effectiveness, and understand their limitations in practice. However, the extended timeline of Chrome’s deprecation created ambiguity about whether third-party cookies could be relied upon as a primary targeting mechanism, leaving many advertisers and publishers in a state of incomplete preparation even after years of discussion.
Regulatory Pressures and the Competition and Markets Authority’s Intervention
The most significant factor influencing Google’s repeated delays and ultimate abandonment of third-party cookie deprecation has been regulatory scrutiny, particularly from the United Kingdom’s Competition and Markets Authority (CMA). The CMA launched its investigation into Google’s Privacy Sandbox proposal in January 2021, concerned that Google’s approach might constitute an abuse of dominance by favoring Google’s own ad tech services over those of competitors. The CMA identified specific competition concerns related to unequal access to functionality associated with user tracking, potential self-preferencing of Google’s own ad tech providers, and potentially unfair terms being imposed on Chrome web users. These concerns reflected a fundamental tension in Google’s position: the company has both the largest browser (Chrome, with approximately 65% market share globally) and the largest ad tech ecosystem, creating incentives to use privacy regulations as a mechanism to strengthen its competitive position.
Rather than immediately proceeding with deprecation, Google accepted commitments to the CMA in June 2021, agreeing to design and develop Privacy Sandbox technologies in ways that would not favor Google’s own ad tech services over competitors. However, even with these commitments in place, the CMA continued to express concerns about Google’s approach throughout 2023 and 2024. In April 2024, the CMA asked Google to pause the deprecation rollout, requesting more time to review industry test results of Privacy Sandbox technologies and assess whether the proposed alternatives could adequately support key advertising functions. The CMA’s position was that deprecating third-party cookies without viable alternatives in place could actually harm competition by making it more difficult for independent publishers and advertisers to operate outside of Google’s walled garden.
The competition concerns raised by the CMA reflect a broader dynamic in the digital advertising industry: Google’s dominance gives it advantages in adapting to a cookieless world that smaller competitors lack. Google owns Chrome, controls the largest ad exchange, operates the largest DSP (Demand-Side Platform), and has access to first-party data from Gmail, Google Search, YouTube, and Android. This integrated position means Google can implement alternatives to third-party cookies more easily than fragmented competitors and can leverage its control of Chrome to favor its own ad tech products. As one analyst noted, the deprecation of third-party cookies could paradoxically strengthen Google’s market position by reducing competition from smaller ad tech companies that lack these integrated assets.
In June 2025, recognizing that Google had decided not to deprecate third-party cookies, the CMA consulted on whether to release Google from the commitments it had made regarding Privacy Sandbox design. In October 2025, after considering stakeholder input, the CMA decided to release Google from these commitments, concluding that its competition concerns no longer applied in light of Google’s decision to maintain third-party cookies. This decision represents a significant validation of Google’s revised approach from a regulatory perspective, suggesting that the CMA viewed the maintenance of third-party cookies as less anticompetitive than the alternatives Google had proposed. The CMA’s analysis implicitly acknowledged that forcing a deprecation without viable alternatives would have harmed competition more than maintaining the status quo.
Beyond the CMA, other regulatory bodies have influenced the cookie deprecation timeline. The European Union’s General Data Protection Regulation (GDPR) and the United Kingdom’s Privacy and Electronic Communications Regulations (PECR) require explicit opt-in consent before most types of cookies can be deployed, meaning that even Google’s maintenance of third-party cookies requires compliance with strict consent requirements. California’s Consumer Privacy Act (CCPA) and similar state privacy laws in the United States create additional compliance burdens, though they typically use an opt-out rather than opt-in model. These regulatory frameworks mean that even where third-party cookies remain technically possible, their practical use is heavily constrained by legal requirements to obtain user consent before deployment.
The Privacy Sandbox Initiative: Aspirations and Failure
When Google announced its intention to deprecate third-party cookies in 2020, it simultaneously launched the Privacy Sandbox initiative, intended to develop privacy-preserving technologies that could replace third-party cookies while still enabling key advertising functions. The Privacy Sandbox represented an ambitious attempt to create new web platform technologies that could support targeted advertising without relying on individual-level cross-site tracking. Over nearly six years of development, the Privacy Sandbox grew to encompass dozens of proposed APIs and technologies, each designed to address specific advertising use cases in privacy-preserving ways.
Key Privacy Sandbox technologies included the Protected Audience API (formerly known as FLEDGE and TURTLEDOVE), which attempted to enable on-device ad auctions where advertiser bidding logic runs in the browser without exposing user data to the ad exchange. The Topics API proposed to categorize users into interest topics based on their browsing history, allowing interest-based targeting without tracking specific websites visited. The Attribution Reporting API aimed to measure advertising effectiveness and attribute conversions to specific ads while preserving privacy through aggregated reporting. Additional technologies like Related Website Sets, CHIPS (Cookies Having Independent Partitioned State), and others attempted to address specific functionality gaps left by cookie deprecation.
Despite years of development and testing, most Privacy Sandbox technologies failed to achieve significant adoption or industry acceptance. Publishers and advertisers raised concerns that the proposed technologies could not adequately support critical functions like brand safety, fraud prevention, and accurate conversion measurement. Many concerns centered on the fact that Privacy Sandbox technologies were deterministic and lacked the flexibility of third-party cookies, which could be instantly adapted to new use cases. Additionally, Privacy Sandbox technologies were heavily dependent on changes to the Chrome browser and required advertisers and publishers to substantially rewrite their targeting, measurement, and attribution systems to accommodate them. The integration challenges were substantial, and many organizations lacked the technical expertise or resources to implement them.
In October 2025, Google officially announced it was retiring most Privacy Sandbox technologies. The company decided to discontinue the Attribution Reporting API, Protected Audience API, Topics API, IP Protection, On-Device Personalization, Private Aggregation, Related Website Sets, SelectURL, SDK Runtime, and other technologies. This decision represented an explicit acknowledgment that the Privacy Sandbox initiative had not succeeded in developing viable alternatives to third-party cookies that the industry was willing to adopt. Google indicated that it would maintain only limited support for CHIPS, FedCM, and Private State Tokens, technologies that had achieved meaningful adoption but represented only a fraction of the original Privacy Sandbox vision.
The failure of the Privacy Sandbox initiative has several implications. First, it demonstrates that developing privacy-preserving alternatives to an entrenched technology like third-party cookies is extraordinarily difficult, requiring coordination across browsers, advertisers, publishers, and technical communities. Second, it suggests that the web advertising industry may not converge on a single replacement technology, but rather on a fragmented ecosystem of different solutions for different use cases. Third, it indicates that some current advertising functionality may be permanently lost as technologies transition away from third-party cookies, requiring advertisers to fundamentally rethink their approaches. Finally, it raises questions about whether the original goal of deprecating third-party cookies while maintaining advertising effectiveness was ever realistic or achievable.
Impact on Digital Advertising and Marketing Effectiveness
The uncertainty surrounding third-party cookie deprecation has created significant concerns throughout the digital advertising industry, with research showing that a substantial majority of advertisers believe cookie deprecation will affect their business more negatively than major privacy regulations like GDPR and CCPA. One study found that 69% of advertisers believe third-party cookie deprecation will have a bigger impact on their business than GDPR and CCPA combined, and 70% feel that digital advertising overall will take a step backward. Similarly, fewer than 46% of advertisers report feeling “very prepared” for marketing without third-party cookies despite years of warning about the deprecation.
The most immediate impact of third-party cookie deprecation is expected to be on targeting and personalization capabilities. Advertisers have historically relied on third-party cookies to build detailed behavioral profiles of individual users based on their browsing activity across multiple websites, enabling sophisticated targeting based on inferred interests and past behaviors. Without this capability, advertisers will struggle to reach specific audience segments and deliver personalized content at scale. This is particularly challenging for consumer packaged goods (CPG) brands that lack first-party direct relationships with consumers and have historically depended on third-party data to identify and reach target audiences.
A second major impact concerns measurement and attribution. Third-party cookies have enabled advertisers to track user journeys across multiple websites and attribute conversions to specific ads or marketing touchpoints. Without this capability, advertisers will find it much more difficult to understand which marketing activities drive which outcomes, making it harder to optimize marketing spend and demonstrate return on advertising investment. Many advertisers who currently measure campaign effectiveness using third-party cookie-based attribution will need to transition to alternative methods like Media Mix Modeling (MMM), which provides less granular insights and requires more sophisticated statistical analysis. Some research suggests that over 50% of conversions globally are already being modeled rather than directly attributed, indicating that measurement challenges are already present even before formal deprecation.
A third category of impacts concerns basic advertising functionality like frequency capping (limiting how many times a user sees the same ad), brand safety (ensuring ads appear next to appropriate content), and fraud prevention. These functions have historically relied on third-party cookies to function across the open web, and alternative mechanisms are less mature and more technically complex. The result is that some advertising functionality may degrade or require substantially different technical implementations.
The impact on digital advertising effectiveness is expected to extend beyond individual advertisers to the broader ecosystem of publishers and websites that depend on advertising revenue. Many publishers lack the direct relationships with consumers that major platforms like Google and Facebook possess, making them particularly dependent on third-party data and advertising networks to generate revenue. As third-party cookies become less available and reliable, smaller publishers may find it more difficult to monetize their inventory, potentially driving greater consolidation and a shift of advertising dollars toward the major “walled gardens” (Google, Facebook, Amazon, Apple) that control first-party user data. This consolidation could ironically harm the privacy objectives that motivated third-party cookie deprecation, as it would concentrate control of user data and advertising in the hands of even fewer, larger companies.
Alternative Solutions: First-Party Data, Contextual Targeting, and Identity Solutions
In response to the challenges posed by third-party cookie deprecation, the advertising industry has developed a diverse ecosystem of alternative solutions, each addressing different aspects of the functionality that third-party cookies previously provided. These solutions fall into several broad categories: first-party and zero-party data collection, contextual targeting, identity resolution, and cookieless measurement approaches.
First-party data represents information collected directly from users through their interactions with a website or brand, including explicit data like registration information and email addresses, as well as behavioral data like browsing history within that site or purchase history. First-party data has become substantially more valuable as third-party data sources have become less reliable, and many businesses are investing heavily in building direct relationships with customers to collect and leverage first-party data. Zero-party data, a subcategory of first-party data, consists of information explicitly provided by users through engagement mechanisms like surveys, quizzes, and preference centers, where users know what data they are providing and why. Both first-party and zero-party data approaches require businesses to invest in building user value propositions that incentivize data sharing, such as personalized experiences, exclusive content, loyalty programs, or special offers.
Contextual targeting represents an alternative approach that focuses on the content and context of the current browsing experience rather than on historical user behavior. Under contextual targeting, ads are selected based on the content of the webpage being viewed, keywords present on the page, or the topic of content the user is currently consuming, without requiring cross-site tracking. Contextual targeting has historical roots in early web advertising and is experiencing a resurgence as advertisers seek alternatives to behavioral targeting. While contextual targeting does not enable the same level of personalization as behavioral targeting based on cross-site history, it can still deliver relevant ads in many contexts and does not raise the same privacy concerns. Research indicates that 79% of UK consumers are more comfortable seeing contextual ads than behavioral ads, suggesting that consumers may prefer contextual approaches even where they perform reasonably well.
Identity solutions represent another major category of alternatives, attempting to create persistent, recognizable identifiers for users across websites while preserving privacy. Unified ID 2.0 (UID2) represents one such solution, using hashed email addresses to create encrypted identifiers that can be shared among publishers and advertisers while preserving user privacy. Other identity solutions like RampID, SharedID, and various deterministic ID approaches attempt to match offline personal information with online behavior to create cross-device user identifiers. These solutions typically require explicit user consent and provide users with visibility and control over their data, addressing privacy concerns while still enabling some degree of personalization. However, identity solutions have faced adoption challenges due to technical complexity, the need for industry coordination, and questions about whether they satisfy privacy regulations in different jurisdictions.
Server-side tracking represents a technical alternative that collects data on the server rather than relying on browser-based mechanisms like cookies. Server-side tracking can mitigate some impacts of browser tracking restrictions and ad blockers, and can provide better control over data quality and privacy compliance. However, server-side tracking requires substantial technical implementation and is not equally viable for all use cases.
First-party data strategies are generally considered more valuable and sustainable long-term than alternative technical solutions, as they represent direct, consented relationships with users that are not dependent on any particular browser technology or regulatory environment. However, building robust first-party data strategies requires investment, time, and organizational change, which not all businesses are positioned to undertake. Additionally, some businesses like many CPG brands lack the direct consumer relationships needed to easily build first-party data strategies. For these businesses, partnerships with retailers that have direct consumer relationships, or with technology platforms that provide identity solutions, may be necessary alternatives.
Regulatory and Compliance Landscape Surrounding Cookies and Privacy
Beyond the specific efforts to deprecate third-party cookies in Chrome, the broader privacy regulatory environment has substantially constrained the practical use of cookies even where they remain technically available. The European Union’s General Data Protection Regulation (GDPR), which took effect in 2018, requires explicit opt-in consent before installing most types of cookies, with only essential cookies needed for basic site functionality exempt from consent requirements. This means that in EU countries, even third-party cookies technically available in Chrome browsers require active user agreement before deployment. Research shows that cookie consent rates in EU countries are substantially lower than in the United States, with countries like Germany and France seeing acceptance rates below 25% for cookies, compared to over 80% acceptance rates in the United States. This suggests that regulatory requirements in the EU have already reduced the practical utility of third-party cookies in that region.
The United Kingdom retained similar requirements after Brexit, with UK GDPR and Privacy and Electronic Communications Regulations (PECR) imposing consent requirements similar to the EU framework. In September 2024, the UK dropped its requirement for double opt-in for cookies in some situations, moving to a single opt-in model, but still requiring active user consent before non-essential cookies are deployed. California’s Consumer Privacy Act (CCPA) and similar state privacy laws in the United States take a different approach, generally using an opt-out model where users can request not to be sold their personal information, rather than requiring prior opt-in. However, even under CCPA’s opt-out model, businesses must provide transparency about their data practices and honor user requests to limit data sharing. In September 2025, California approved revisions to CCPA regulations that take effect January 1, 2026, expanding requirements around automated decision-making technology, cybersecurity audits, and risk assessments.
Brazil’s Lei Geral de Proteção de Dados (LGPD) and other emerging privacy frameworks worldwide increasingly follow either the EU’s opt-in model or require explicit user consent before personal data collection. This regulatory fragmentation means that many large advertisers and publishers must maintain different cookie handling approaches for different geographic regions, substantially complicating their technical implementations. Consent Management Platforms (CMPs) have emerged as a major category of technology to help businesses manage these compliance requirements, automatically adapting cookie handling based on user location and applicable regulations.
The practical implication of this regulatory landscape is that even where third-party cookies remain available, their effective reach and utility has been substantially constrained by privacy regulations. In many cases, only a minority of users have consented to allow third-party cookies, meaning that advertisers must develop measurement and targeting approaches that function even when a substantial percentage of their traffic cannot be tracked. This regulatory constraint has, in some ways, already accomplished some of the privacy goals that third-party cookie deprecation was intended to achieve, by making cookies less effective as a ubiquitous tracking mechanism.
Implementation Challenges and Technical Complexity for Businesses
Despite years of warning about third-party cookie deprecation, many businesses continue to struggle with understanding and preparing for the transition to alternative technologies and data sources. Several surveys have found that significant percentages of marketers report being unprepared or only partially prepared for a world without third-party cookies, despite the extended timeline and available resources. Implementation challenges stem from several sources.
First, there is no single, universal replacement for third-party cookies that can maintain all the functionality while addressing privacy concerns. Instead, businesses must develop customized solutions combining multiple approaches: first-party data collection, contextual targeting, identity solutions, server-side tracking, machine learning-based modeling, and other techniques. This fragmented landscape requires businesses to make strategic decisions about which solutions to invest in, how to integrate them with existing systems, and how to measure their effectiveness.
Second, implementing alternative solutions often requires substantial technical investment and organizational change. First-party data strategies require building data infrastructure, customer relationship management systems, and user value propositions that encourage data sharing. Identity solutions require integrating new partners and technology platforms. Server-side tracking requires developing new data processing infrastructure. These changes cannot typically be made quickly or cheaply, particularly for businesses with large, complex advertising technology stacks.
Third, many businesses lack the in-house technical expertise or resources needed to evaluate, implement, and optimize alternative solutions. Small and medium-sized businesses may lack dedicated data science or marketing technology teams, making it difficult to evaluate which solutions are most appropriate for their business models. Even large businesses may find themselves stretched thin trying to simultaneously manage existing cookie-based systems while experimenting with alternatives.
Fourth, the practical effectiveness of many alternative solutions remains uncertain and varies substantially by business model, industry, and market. While first-party data generally performs better than third-party data, many businesses still lack robust first-party data programs and struggle to quantify the value of investing in building them. Contextual targeting performs reasonably well in many situations but may not be adequate for all use cases. Identity solutions are promising but face adoption challenges and may not be suitable for all geographies or industries.
Finally, the extended timeline of uncertainty has created perverse incentives, with many businesses adopting a wait-and-see approach rather than proactively investing in alternatives. With Google’s repeated delays and ultimate decision to maintain third-party cookies, some businesses have shifted resources away from alternative solution development and back toward optimizing their existing third-party cookie-based systems. However, this approach is risky given that browsers other than Chrome continue to restrict third-party cookies, and regulatory requirements continue to evolve.
User Consent, Opt-In Rates, and Consumer Preferences
An important dimension of the third-party cookie deprecation story concerns actual user behavior and consumer preferences around data tracking and personalized advertising. Multiple data sources provide insights into how users respond when given explicit choices about data sharing and tracking.
Apple’s App Tracking Transparency (ATT) framework, introduced with iOS 14.5 in 2021, requires apps to obtain explicit user permission before tracking behavior across other apps and websites on iOS devices. When ATT was first introduced, only about 16% of users chose to allow tracking, substantially lower than historical rates of consent for similar data collection approaches. However, over time, ATT opt-in rates have increased as users became more familiar with the framework and as apps improved their prompt design and messaging. As of Q2 2025, industry-wide average ATT opt-in rates had reached approximately 35%, with substantial variation by app category and geography. Gaming apps achieve the highest opt-in rates at approximately 50% overall, with hyper-casual games reaching 43% and sports games reaching 50%, likely because gamers understand that personalized advertising enables them to discover games they will enjoy. In contrast, education apps have historically had very low opt-in rates, though they improved from 7% in 2023 to 14% in 2025, suggesting that improved prompt design can substantially influence user behavior. Geographically, Brazil achieved the highest opt-in rate at 50%, followed by the United Arab Emirates at 49%, while Australia and Canada had lower opt-in rates at 27% and 29% respectively.
The ATT data suggests that when users are explicitly asked whether to allow tracking, substantial majorities choose to opt out, but that this result is not universal and can be influenced by prompt design, user education, timing, and the perceived value exchange between the user and the app. Additionally, the fact that opt-in rates vary substantially across categories and regions suggests that user preferences around data sharing are context-dependent rather than uniform.
Research on cookie consent similarly shows substantial variation in how users respond to consent prompts. In France, approximately 28% of users consistently provide consent for cookies, with an additional 37% demonstrating a recurring pattern of acceptance, while 5% persistently refuse and 30% actively minimize their interactions with cookies. Globally, cookie acceptance rates vary substantially by country, with Poland achieving a high consent rate of 64%, while the United States has one of the lowest at 32%. These variations likely reflect differences in regulatory frameworks, cultural attitudes toward privacy, trust in companies and institutions, and the quality and transparency of consent prompts.
Consumer preferences around targeted advertising versus contextual advertising also provide insights into user preferences. Research shows that 79% of UK consumers express greater comfort with contextual advertising than behavioral advertising, suggesting that consumers prefer advertising approaches that don’t rely on personal data collection and tracking. This indicates that businesses might benefit from emphasizing contextual targeting approaches in their marketing messages, framing them as respecting user privacy rather than merely as functional necessities. However, despite concerns about behavioral targeting and privacy, many consumers still accept cookies when provided with clear value propositions, suggesting that data sharing is acceptable when users understand why their data is being collected and what benefits they receive in return.
Competitive Concentration and the Rise of Walled Gardens
One of the most significant and concerning implications of third-party cookie deprecation is the expected acceleration of competitive concentration in digital advertising, with the largest platforms—Google, Meta (Facebook), Amazon, Apple, and others—substantially increasing their market dominance at the expense of smaller, independent ad tech companies and publishers. This dynamic arises from the fundamental asymmetry in how different businesses are positioned relative to the loss of third-party cookies.
Large platforms like Google possess first-party user data from multiple sources: Google Search generates search data, YouTube generates video watching data, Gmail generates email and web behavior data, Android generates mobile behavior data, and Chrome generates web browsing data. This first-party data is substantially more valuable in a cookieless world than third-party data, as it comes directly from known, authenticated users and is subject to fewer privacy restrictions. These platforms can continue to target users with precision and deliver personalized advertising even as third-party cookies become less available to smaller competitors. Moreover, these platforms control key infrastructure: Google controls the Chrome browser and a large advertising exchange, Meta controls Facebook and Instagram with billions of users, and Amazon controls a retail environment with purchase data.
In contrast, smaller independent publishers and ad tech vendors lack first-party data at the necessary scale, must rely on third-party data brokers and aggregation approaches, and lack control of key infrastructure. As third-party cookies become less reliable and user consent for alternative tracking approaches remains limited, smaller businesses find themselves disadvantaged relative to the large platforms. This dynamic is predicted to accelerate the “walled garden” phenomenon, where advertising dollars increasingly concentrate on platforms like Google and Facebook that can operate effectively without reliance on third-party cookies.
Research suggests this dynamic is already underway. Among walled gardens identified in 2023, Google commanded approximately 40% of U.S. digital advertising dollars, Facebook approximately 18%, Amazon approximately 7%, with the remaining walled gardens (including Chinese platforms like TikTok, Baidu, and Tencent) combining for approximately 9%. The open internet (digital properties not controlled by a walled garden) represented approximately 22% of global digital ad expenditure in 2023 but is projected to decline to only 17% by 2027. This trend represents a substantial consolidation of power in the hands of a few large corporations.
One potentially concerning implication of this consolidation is that it could actually harm privacy in the longer term, despite the privacy motivation for deprecating third-party cookies. With more advertising controlled by fewer large companies, those companies would face less competitive pressure to be transparent or restrained in their use of user data, potentially leading to more aggressive first-party data collection and utilization by the dominant platforms. The walled garden companies have demonstrated willingness to use their market power to influence regulation and define technical standards in ways that benefit their competitive positions.
Some smaller publishers are attempting to respond to this challenge through partnerships and “hedged gardens,” where multiple small publishers or ad tech companies pool their first-party data to create larger datasets suitable for targeting. Examples include partnerships between Walmart and The Trade Desk that allow advertisers to leverage Walmart’s first-party retail data across third-party publisher networks. However, these approaches face significant challenges in achieving scale and coordination comparable to that of the major walled gardens.
Future Outlook and Strategic Recommendations for Business Preparation
Looking forward, the most realistic assessment of the third-party cookie landscape is that deprecation will continue to gradually reduce the effectiveness and availability of third-party cookies, even if Google does not formally eliminate them from Chrome. This gradual decline stems from multiple factors: regulatory requirements in jurisdictions like the EU reduce consent rates, other browsers continue to block third-party cookies entirely, increasing adoption of privacy-focused browser extensions and tracking prevention tools, and user awareness of privacy issues drives more informed consent decisions. The result is that third-party cookies will continue to be less reliable and less effective, even if not completely eliminated.
For businesses, this reality suggests several strategic recommendations. First, all businesses should prioritize building robust first-party data strategies, recognizing that first-party data will become increasingly valuable as third-party data sources become less reliable. This requires investment in building direct customer relationships, collecting explicit consent for data processing, creating value propositions that incentivize data sharing, and developing data infrastructure to store, manage, and leverage first-party data. Businesses that succeed in building strong first-party data strategies will be better positioned to compete in the coming years.
Second, businesses should diversify their data sources and targeting approaches rather than relying on any single solution. A hybrid approach combining first-party data, contextual targeting, identity solutions, and cookieless measurement techniques is more likely to prove effective than betting on a single technology. This requires ongoing experimentation, testing, and optimization to determine which approaches work best for specific business objectives and industries.
Third, businesses should invest in understanding and complying with evolving privacy regulations in the jurisdictions where they operate. Privacy regulations will continue to evolve, particularly around automated decision-making and AI applications, and proactive compliance efforts will be more cost-effective than reactive responses to regulatory enforcement actions. Implementing consent management platforms and maintaining detailed records of data practices and user consents will be increasingly important.
Fourth, businesses should be realistic about the limitations of available alternatives to third-party cookies and adjust their performance expectations and measurement approaches accordingly. Some advertising functionality that was taken for granted in the third-party cookie era may not be available or may be substantially diminished in the cookieless era. Businesses should plan for this scenario rather than expecting alternatives to deliver identical performance to third-party cookies. Measurement and attribution may be less precise, some targeting capabilities may be reduced, and some advertising use cases may no longer be viable.
Fifth, for advertisers and publishers without substantial first-party data, exploring partnerships with platforms that do possess first-party data may be necessary, even if these partnerships represent less independence than directly owned data sources. Retailers with customer databases, platforms with large logged-in user bases, and identity solution providers can all represent viable partnerships for businesses seeking to maintain effective advertising in a cookieless world.
Finally, businesses should continue to monitor ongoing developments in the privacy technology landscape, regulatory environment, and industry standards, recognizing that this area remains fluid and subject to continued change. The October 2025 announcement of Privacy Sandbox deprecation and the CMA’s release of Google from its Privacy Sandbox commitments suggest that the industry may be entering a new phase characterized by greater pragmatism and acceptance that a single replacement technology for third-party cookies may not emerge. In this environment, flexibility and adaptability will be as important as specific technical investments.
The Evolving Horizon: Anticipating the Post-Cookie Future
The journey toward third-party cookie deprecation represents one of the most complex technological, regulatory, and competitive transformations in digital marketing history. What began in 2020 as Google’s clear announcement of a planned phase-out of third-party cookies by 2022 has evolved through multiple delays, regulatory interventions, industry objections, and ultimately complete strategic reversals, arriving at a point in October 2025 where Google has abandoned the Privacy Sandbox initiative, maintained third-party cookies in Chrome, and released the regulatory commitments that previously constrained its approach. This journey demonstrates the profound difficulty of deprecating an entrenched technology that is so central to digital advertising infrastructure, the importance of regulatory oversight in preventing potential anticompetitive outcomes, and the limitations of attempting to develop privacy-preserving alternatives that preserve all existing functionality.
Despite Google’s decision to maintain third-party cookies in Chrome, the broader trend toward a world with reduced reliance on third-party cookies is durable and unlikely to reverse. Safari, Firefox, and other browsers will continue to block third-party cookies, regulatory requirements will continue to constrain their practical use, and user consent rates will likely remain substantially below historical levels. The result is a de facto transition away from third-party cookies even if not a formal, universal deprecation. For businesses, this reality necessitates proactive adaptation regardless of Google’s specific stance on deprecation.
The most important implication of the third-party cookie timeline is that businesses must shift their focus from tactical optimization of third-party cookie utilization toward strategic development of first-party data capabilities, privacy-centric marketing approaches, and diverse solutions for targeting and measurement. Businesses that make this transition successfully will be better positioned to compete effectively in the coming years, while businesses that continue to rely primarily on third-party cookies will find themselves increasingly disadvantaged. The optimal path forward involves treating third-party cookie deprecation not as a crisis to be averted but as an opportunity to build more sustainable, privacy-respecting relationships with customers while simultaneously improving regulatory compliance and brand reputation. The businesses that embrace this framing and invest accordingly will be the winners in the cookieless era.
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