Whatever goodwill Google earned in the past few years that it has been fighting off advertising and user tracking abuses may have gone down the train in an instant thanks to its proposed solution. The Federated Learning of Cohorts or FLoC is promoted to be a better strategy that protects people’s privacy while still giving advertisers something they can profit from. Privacy advocates, however, are raising alarms over what they deem to be an even worse technology and Chromium-based browser makers like Brave and Vivaldi are committing to fighting off FLoC in all its forms.
In a nutshell, FLoC trades individual user tracking and fingerprinting for group (cohort) identification based on similar browsing histories of members in that group. Google argues that it is more private since advertisers and sites only see group IDs and the browsing history data never leaves the device (federated learning). Google also promises that it won’t create cohorts that are associated with sensitive topics to ensure the security and privacy of members of that group.
Many privacy advocates aren’t buying it, though, and consider FLoC an even worse solution than the problem it tries to fix. In addition to potentially violating laws like the GPDR, critics also point out that FLoC collects more private data in the form of browsing history, something that even tracking cookies don’t do. While unique individual identities might be hidden behind cohorts, the data held by browsing history can still be considered as something private, especially when it will be easy to develop profiles for members of that group.
Google’s FLoC is, of course, only applicable to its own Chrome browser but apparently also has traces in the open source Chromium engine that is used by Brave, Vivaldi, Microsoft Edge, and many other smaller browsers. For that reason, Brave and Vivaldi have published rather scathing posts about FLoC and have promised to block it in any form. Brave will additionally block FLoC interaction for Chrome users visiting its website.
Google’s replacement for third-party tracking cookies is already under legal scrutiny, especially over its potential for anticompetitive abuse. When Chrome completely blocks such cookies, advertisers and sites may be forced to switch to FLoC and Google’s advertising platform to continue making a living from ads on Chrome browsers. Brave, however, points out that FLoC may actually be harmful even for sites and advertisers as its system will favor larger entities that can steal audiences away from niche or smaller players.