The biggest web browser in the world, Google Chrome, is developing the Privacy Sandbox<\/a> to create a cookieless, user- and advertiser-friendly environment. However, the initiative is being scrutinized for several reasons, including gaining a dominant position in the AdTech market. Thus, the Privacy Sandbox project needs to evolve to adapt to market requirements.<\/p>\n In August 2019, Alphabet Inc.\u2019s subsidiary, Google Chrome, launched its Privacy Sandbox initiative to develop a set of open standards to enhance privacy on the web. The company asked the AdTech industry for feedback.<\/p>\n The initial reactions were mixed. While some stakeholders welcomed the initiative as a necessary step toward protecting user privacy, others expressed concerns<\/a> about its potential impact on the advertising ecosystem.<\/p>\n Industry groups such as the Interactive Advertising Bureau (IAB) and various digital marketing firms worried that the Privacy Sandbox could limit their ability to track users effectively, thereby reducing the precision and profitability of targeted advertising.<\/p>\n On January 7, 2021, the British Competition and Markets Authority<\/a> (CMA) launched an investigation into Google\u2019s project to prevent Google from gaining a dominant position in the AdTech market. The investigation is backed up by the Competition Act 1998<\/a>.<\/p>\n Alphabet\u2019s companies committed to cooperating with the CMA<\/a> in scrutinizing and overseeing Google\u2019s Privacy Sandbox proposals. Over the next three years, each quarter, the CMA has published its latest update report on the implementation of Google\u2019s Privacy Sandbox commitments<\/a>.<\/p>\n The British body welcomed the industry to participate in open consultations.<\/p>\n All of these factors added up to Privacy Sandbox\u2019s evolution, especially in terms of providing proper tech solutions.\u00a0<\/p>\n Here\u2019s how it went.<\/p>\n Google\u2019s Privacy Sandbox includes several key APIs designed to enhance privacy while maintaining functionality for advertisers. Ever since the project was launched, the APIs have been evolving.<\/p>\n The two APIs at the top of the list went the longest way in terms of aligning them with the market\u2019s requirements.<\/p>\n On January 14, 2020, Chrome published an intention to implement a Federated Learning of Cohorts (FLoC) API<\/a>, the original solution designed for ad targeting in the Privacy Sandbox. Its concept was to group users into cohorts based on similar browsing behaviors, allowing interest-based advertising without individual tracking.\u00a0<\/p>\n In January 2021, Google claimed that FLoC was at least 95% as effective as third-party cookies<\/a> for tracking.<\/p>\n However, AdExchanger reported<\/a> skepticism within the AdTech industry about Google\u2019s claim and its methodology. FLoC aimed to democratize access to user browsing history by grouping users into cohorts, which would be shared with every website they visit instead of using individual tracking techniques.<\/p>\n The Electronic Frontier Foundation (EFF) also criticized FLoC<\/a>, calling it a breach of user trust. The EFF\u2019s Cory Doctorow acknowledged the benefit of removing third-party cookies but opinioned FLoC<\/a> for potentially making Google a gatekeeper of user privacy.<\/p>\n In April 2021, DuckDuckGo advised against using Chrome<\/a>, highlighting that users could be included in FLoC without their consent. The company emphasized that any behavioral tracking mechanism should be opt-in and free of dark patterns. DuckDuckGo updated its Chrome extension to block FLoC interactions.<\/p>\n Brave, another Chromium-based browser, announced it would disable FLoC<\/a> and criticized Google\u2019s approach as insufficient for genuine privacy protection. Major browsers, including Microsoft Edge, Vivaldi, and Opera, also declined to implement FLoC<\/a>.<\/p>\n Additionally, several companies, such as GitHub, Drupal, and Amazon, opted to disable FLoC<\/a> by using specific HTTP headers.<\/p>\n Also, The Economist reported concerns about FLoC<\/a> potentially grouping people by sensitive characteristics like race or sexuality.<\/p>\n The initial version of FLoC ran from Chrome 89 to 91 and ended on July 14, 2021<\/a>. On January 25, 2022<\/a>, Google introduced FLoC\u2019s replacement: the Topics API<\/a>.<\/p>\n FLoC grouped users into cohorts based on similar browsing behaviors. Each cohort represented a cluster of users with similar interests and browsing patterns.<\/p>\n The Topics API assigns users to general-interest categories (e.g., sports, travel, technology) based on their browsing history over a short period. Only a few recent topics are shared with websites, and these topics are rotated periodically to protect user privacy.\u00a0<\/p>\n The Topics API aims to address the primary FLoC concerns, such as fingerprinting and lack of transparency. This approach has received a more favorable response from privacy advocates and the AdTech industry stakeholders.<\/p>\n The evolution of frameworks for remarketing and custom audience creation started with the method called TURTLEDOVE \u2014 Two Uncorrelated Requests, Then Locally-Executed Decision On Victory.<\/p>\n TURTLEDOVE\u2019s main feature was that all auction choices would be made in the browser, not on ad servers. Excluding data sharing would, in theory, prevent malicious actors from stealing bidstream data and using it to create user profiles.\u00a0<\/p>\n However, Google had to change its proposal due to the industry\u2019s criticism<\/a>:<\/p>\n TURTLEDOVE\u2019s follower was FLEDGE \u2014 First Locally-Executed Decision over Groups Experiment.<\/p>\n FLEDGE is partly built on the TURTLEDOVE method. It enables on-device auctions run in the browser to choose relevant ads from websites the user has previously visited, but it also introduces additional capabilities like custom audiences, more complex auction logic, and the use of a trusted server for specific functions.<\/p>\n FLEDGE was rebranded in April 2023 to Protected Audience<\/a>, and Google is further working on enhancing the solution. The latest update, from January 10, 2024<\/a>, mentions transitioning away from event-level reporting and requiring the use of Fenced Frames no sooner than in 2026.<\/p>\n Google still develops Privacy Sandbox standards<\/a>. The company believes that Internet technology has and will evolve, and it\u2019s not necessary to deliver complete technical designs but to improve them along the way.\u00a0<\/p>\n The road to the point where Google will be certain about going live with the Privacy Sandbox is rather bumpy. Google\u2019s key announcements illustrate the complexities of the project:<\/p>\n As a result of the CMA\u2019s involvement in the Privacy Sandbox project, Criteo\u2019s tests on the Privacy Sandbox<\/a> from 2024, and IAB Tech Lab\u2019s report<\/a> criticizing Privacy Sandbox functionality and claiming the industry \u201cisn\u2019t ready\u201d for the shift, Google eventually redesigned an idea for introducing the Privacy Sandbox on the web.<\/p>\n The simultaneous introduction of Google\u2019s Privacy Sandbox and the phasing out of third-party cookies was to mark a shift in how data collection and usage would be managed within the digital advertising ecosystem.\u00a0<\/p>\nWhen Google Announced its Privacy Sandbox<\/span><\/h2>\n
The Evolution of Advertising Solutions in Google\u2019s Privacy Sandbox<\/span><\/h2>\n
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FLoC Criticized and Replaced by Topics API<\/span><\/h3>\n
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FLoC vs Topics API<\/span><\/h4>\n
TURTLEDOVE Modified Into Protected Audience API<\/span><\/h3>\n
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Will Google\u2019s Privacy Sandbox Ever Go Live?<\/span><\/h2>\n
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What Impact on AdTech Does the Privacy Sandbox Have?<\/span><\/h2>\n