What's going to happen is that sites will enumerate which FLoC IDs represent which set of interests, and just use send that data off together with whatever uniq

What's going to happen is that sites will enumerate which FLoC IDs represent which set of interests, and just use send that data off together with whatever unique ID they're already tracking you with. You can do this by just setting up a new profile and visiting various pages, then checking what the FLoC ID is. See here for an example by Jonathan Foote: https://twitter.com/footePGH/status/1380568421490905088 https://twitter.com/footePGH/status/1380568421490905088 It's based on your browsing history, so companies will now be able to get an aggregate of your interests without having to actually track you across other sites.