28th January 2022

POV: Google to replace FLoC with new Topics API


Google is replacing the Federated Learning of Cohorts (FLoC), its original cookie alternative, with a new proposed alternative Topics API.

Details and Implications:

It was announced this week that Google is scrapping plans to move ahead with FLoC, which was Google’s project to replace cookies with interest-based advertising. FLoC had received criticism for potentially posing privacy risks, such as making it easier for advertisers to identify consumers from browser fingerprinting.  The company is now focusing on Topics for when cookies are no longer used on its Chrome browser in 2023 (other browsers such as Firefox and Safari already block third-party cookies). At this stage though, Topics is still a proposal and the final approach may evolve.

Topics is an interest-based advertising approach. It will work by gathering information on a user’s interests as they move around the web and categorise users based on broad interests, such as ‘fitness’ or ‘travel’. Each website that uses the Topics API will be assigned an overall category.  Chrome will then determine a user’s five top interests or ‘topics’ each week, based on their web activity. A user’s data will be held for three weeks only, and it will all be stored on the user’s browser.

When a user visits a site that supports Topics for ad purposes, the API will select three topics they are interested in (one for each week it has data for) which will be selected randomly from their top five topics of each week. This information will be shared with the site and its advertising partners for them to decide which ad to show. The intention with this random allocation is to make it harder for sites to cross-correlate the same user. This will give users more privacy and they will also have more control, as users will be able to review and remove topics from their lists and turn off Topics entirely too.

Topics categories will be limited to 300 different topics to begin with, with plans to extend this in future and the topics will not include any sensitive categories such as gender or race. The non-sensitive categories are yet to be fully defined by Google, but it is expected it will follow GDPR categories and guidelines.

Google is using learnings from its FLoC project to develop Topics but has said that Topics has a different design and functionality to FLoC.


Topics is one element of Google’s wider Privacy Sandbox plan to bring about the end of third-party cookies in Chrome. The move away from FLoC to Topics indicates a key shift in Chrome’s approach to creating privacy preserving advertising solutions and its overall approach for interest-based advertising capabilities.

The implications for advertisers when these changes come into play are still unclear, so we will have to see how Google’s plans continue to change before third-party cookies are fully phased out at the end of 2023.  

Further reading

TechCrunch | Campaign | The Verge

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