Google Chrome begins FLoC early testing

The Google Chrome browser has now begun early developer testing of Federated Learning of Cohorts (FLoC) to replace third-party cookies. In the announcement, Google stated that it is pleased to see that other browsers also start to block third-party cookies by default, although many publishers now rely on cookie-based advertising to support their content work. In addition, through the interception of cookies, device fingerprinting and other privacy-infringing solutions have also increased.

FLoC is Chrome’s choice to replace third-party cookies. According to the announcement description, it has three characteristics:

  • You’re part of a crowd. FLoC allows you to remain anonymous as you browse across websites and also improves privacy by allowing publishers to present relevant ads to large groups (called cohorts). Cohorts are defined by similarities in browsing history, but they’re not based on who you are individually. In fact, which cohort you are in frequently changes as your browsing history changes. Of course, when you want an individual experience, you can still sign into websites and share the personal information you choose.
  • FLoC doesn’t share your browsing history with Google or anyone. With FLoC, your browser determines which cohort corresponds most closely to your recent web browsing history, grouping you with thousands of other people who have similar browsing histories. The identification number of the cohort is the only thing provided when requested by a site. This is different from third-party cookies, which allow companies to follow you individually across different sites. FLoC works on your device without your browsing history being shared. Importantly, everyone in the ads ecosystem, including Google’s own advertising products, will have the same access to FLoC.
  • Chrome browser won’t create groups that it deems sensitive. Before a cohort becomes eligible, Chrome analyzes it to see if the cohort is visiting pages with sensitive topics, such as medical websites or websites with political or religious content, at a high rate. If so, Chrome ensures that the cohort isn’t used, without learning which sensitive topics users were interested in. We have created a detailed technical paper on how this works. And of course, sites can also opt out of FLoC, meaning the browser will not include visits to that site when determining a cohort.

At present, the Chrome browser has been tested by developers of FLoC in a small number of users in Australia, Brazil, Canada, India, Indonesia, Japan, Mexico, New Zealand, Philippines, and the U.S. After that, the testing scope will be expanded globally.