Google’s Topics API: What you need to know

Google’s third-party cookie alternative for advertising has changed again.

The goal is to protect the data privacy of internet users — but in a different way. The change will impact future targeting on the Google Ads ecosystem, including the Google Display Network, Google search ads, YouTube advertising and more. Here’s what we know so far.

Chrome, cookies and cohorts

Last year, Google announced a postponement of third-party cookie blocking in its Chrome browser. The new target date is late 2023. This delay would give Google more time to develop a replacement ad-targeting strategy: Federated Learning of Cohorts (FLoC). But Google recently announced a change of plans. FLoC is out. Topics is in.

Google Topics API

Here’s how the Topics application programming interface (API) works.

First, Topics API looks at an individual user’s browsing history for the past three weeks. Then, Topics API uses that history to identify topics the user is interested in — one topic from each week of browsing.

Up to five topics are linked to the user’s browser, but no data is saved on any external server. Topic selection occurs on the user’s device and is saved there for three weeks. When a user visits a participating site, Topics API shares three topics the user is interested in with that site and its advertising partners.

The plan will start with about 300 topics. Ben Galbraith, Chrome product director, says this number is just a starting point — the number of topics could grow into the thousands. He also notes that Topics is an intersection of IAB’s Content Taxonomy V2 and Google’s advertising taxonomy review.

As with most new Chrome features, Google plans to launch a developer trial. Based on the trial results, user controls and other technical aspects will be massaged before Topics is released to a wider audience.

The cookie crumbles

Today, Google uses third-party cookies and behavioral targeting to serve relevant ads to users. But because each cookie has a unique identifier for each individual browser user, Google is moving toward a more data-privacy-driven solution.

Google’s shift to Topics API makes data privacy a priority. It puts an end to behavioral targeting — and marks a new beginning for contextual and interest-based targeting.