EFF urges Google to ground its FLoC: 'Pro-privacy' third-party cookie replacement not actually great for privacy

EFF urges Google to ground its FLoC: 'Pro-privacy' third-party cookie replacement not actually great for privacy

With the arrival of Google Chrome v89 on Tuesday, Google is preparing to test a technology called Federated Learning of Cohorts, or FLoC, that it hopes will replace increasingly shunned, privacy-denying third-party cookies.


Bennett Cyphers, staff technologist at the Electronic Frontier Foundation, argues FLoC is "a terrible idea," and urges Google to refocus its efforts on building a web that serves the people who use it.

"Instead of re-inventing the tracking wheel, we should imagine a better world without the myriad problems of targeted ads," he said in a blog post.


Third-party cookies – files slipped into web surfers' browsers containing identifiers and other data that marketers use to track people across different websites for the sake of ad targeting and analytics – turn out to be pretty bad for privacy. But because they're lucrative for the ad business, Google and other companies have been trying to come up with alternative tracking tech that passes muster with privacy regulators.

FLoC is one component in Google's so-called Privacy Sandbox, a set of technical proposals that Google and other ad tech firms have been working on to replace the third-party cookie, which Google last year said it would stop supporting after competing browser makers began blocking them by default.


"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," explains Cyphers. "Each user’s browser will share a cohort ID, indicating which group they belong to, with websites and advertisers."


Selling by the group


FLoC cohorts are intended to represent large, general interest groups; more specific behavioral ad targe ..