Google’s FLoC Is a Terrible Idea | Electronic Frontier Foundation

While Google's PR team is busy making the most of their decision to not track you on websites and advertise based on that, they are introducing new technologies that can do the same thing via a different means.

FLoC is designed to help advertisers perform behavioral targeting without third-party cookies. A browser with FLoC enabled would collect information about its user’s browsing habits, then use that information to assign its user to a “cohort” or group. Users with similar browsing habits—for some definition of “similar”—would be grouped into the same cohort. Each user’s browser will share a cohort ID, indicating which group they belong to, with websites and advertisers. According to the proposal, at least a few thousand users should belong to each cohort (though that’s not a guarantee).

If that sounds dense, think of it this way: your FLoC ID will be like a succinct summary of your recent activity on the Web.

This is going to be a space worth paying close attention to if you are focused on privacy on the web.