Google proposes new Topics API for interest-based ads

25 Jan 2022

Image: © PixieMe/

With Topics, Google is aiming to balance privacy concerns with the demands of the ad industry.

As it looks to replace third-party cookies with interest-based advertising, Google has proposed a new project today (25 January) that is said will help advertisers target users in way that protects privacy.

Google said last year that it was going to stop tracking users’ browsing activity for the purpose of selling ads, as a result of growing privacy concerns. At the time, a Google blogpost citied figures that said 72pc of people feel that almost all their online activity is being tracked by tech firms and advertisers.

A proposed third-party cookie ban in Chrome, intended to come into effect in 2022, was pushed back to 2023. For the privacy conscious, the ban was a win. But for the vocal ad industry, it was potentially disastrous and has been a source of tension with Google.

To balance these concerns, Google launched the Privacy Sandbox, an initiative to create technologies that both protect user privacy and give companies and developers tools to building thriving online businesses.

Federated Learning of Cohorts (FLOC) was Google’s controversial interest-based ad project that was proposed. In this approach, users would still be tracked but grouped together based on certain interests that advertisers could then display ads to.

The proposal didn’t go down well with advertisers and there were concerns it could still be used to track users. But now, FLOC is being replaced with Topics.

What is Topics?

Topics is an API that runs on Chrome to place websites visited by users into categories, such as fitness, travel and sports, to represent their top interests for any given week based on their browsing history.

Illustration of cookie-based system on the left and the proposed Topics based on interests on the right.

Cookies v Topics. Image: Google

These topics are then shared with advertisers who can use the information to tailor their ads to the preferences of users. Google said that topics are only saved for three weeks and old topics are deleted.

“Topics are selected entirely on your device without involving any external servers, including Google servers. When you visit a participating site, Topics picks just three topics, one topic from each of the past three weeks, to share with the site and its advertising partners,” Vinay Goel, product director of Privacy Sandbox, wrote in a blog post.

He said that Topics enables browsers to give users “meaningful transparency and control over data”. In Chrome, users will be able to see their topics and remove any they don’t like, or disable the feature entirely if they wish to.

Google has designed Topics to exclude sensitive categories such as gender or race. Goel said that because Topics is powered by the browser, it provides users with “a more recognisable way to see and control” how their data is shared when compared to the third-party cookie system.

A developer trial of Topics with user controls will be launched on Chrome soon, which will enable website developers and the ad industry to try it out and give feedback.

“The Privacy Sandbox is one of the most ambitious, important efforts we’ve ever undertaken, and we’re profoundly grateful for the engagement, feedback and partnership from everyone who’s participated,” Goel added.

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Vish Gain is a journalist with Silicon Republic