Google on Tuesday announced that it is abandoning its controversial plans for replacing third-party cookies in favor of a new Privacy Sandbox proposal called Topics, which categorizes users' browsing habits into approximately 350 topics.

The new mechanism, which takes the place of FLoC (short for Federated Learning of Cohorts), slots users' browsing history for a given week into a handful of top pre-designated interests (i.e., topics), which are retained only on the device for a revolving period of three weeks.

Subsequently, when a user visits a participating site, the Topics API selects three of the interests — one topic from each of the past three weeks — to share with the site and its advertising partners. To give more control over the framework, users can not only see the topics but also remove topics or disable it altogether.


By labeling each website with a recognizable, high-level topic and sharing the most frequent topics associated with the browsing history, the idea is to facilitate interest-based advertising by showing users more relevant ads, without needing to know the specific sites that have been visited.

Topics, which is expected to be launched as a developer trial in Chrome browser, employs machine learning to infer topics from hostnames and is designed to exclude sensitive categories, such as sexual orientation, religion, gender, or race, Google pointed out.

"Because Topics is powered by the browser, it provides you with a more recognizable way to see and control how your data is shared, compared to tracking mechanisms like third-party cookies," Vinay Goel, privacy director of Privacy Sandbox, said.

"And, by providing websites with your topics of interest, online businesses have an option that doesn't involve covert tracking techniques, like browser fingerprinting, in order to continue serving relevant ads," Goel added.

The development comes exactly seven months after Google said it was delaying the rollout of FLoC from early 2022 to late 2023 following sustained blowback from privacy advocates and publishers alike, prompting the company to acknowledge that "more time is needed across the ecosystem to get this right."


Topics also hopes to rework some of the core concerns with FLoC, which was branded by the Electronic Frontier Foundation (EFF) as a terrible idea that created more privacy risks for users.

Particularly, FLoC drew criticism for constructing "cohorts" from a combination of different online interests that could lead to classifying users in a manner that could increase the risk of discrimination. What's more, should a cohort be deemed too small, then it could be combined with other tracking information to uniquely identify an individual, effectively undermining the privacy protections.

The overhaul is part of the search giant's plans to replace third-party cookies over privacy concerns. Privacy Sandbox, as the efforts are called, aim to develop privacy-focused alternatives that restrict tracking of users on the web while also maintaining existing web capabilities, including advertising.

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