The era of tracking users all across the web using third-party
cookies is coming to a close; that type of cookie is
something of a zombie at this point. All of the major browsers, save
one, are blocking third-party cookies by default and the holdout, Google
Chrome, plans to make that change next year. But Google, which has a
business model built around advertising that benefits greatly from the
status quo, has offered up an alternative scheme to “replace” third-party
cookies. The Federated Learning of
Cohorts (FLoC) is an in-browser mechanism to pigeonhole users in a way
that will be useful to advertisers, but the only reason the idea has any
traction at all is because it is being implemented in Chrome—the dominant
browser today.

Source: LWN.net – [$] A replacement for third-party cookies?