Google’s FLoC: What is it and why so many other browsers are against it

FLoC is Google’s alternative to third-party cookies and is based on machine learning. This will allow the browser, any browser, to anonymously study how users are browsing and then group them in ‘cohorts’.

Privacy-focused browser DuckDuckGo, Brave and Vivaldi have all warned users against FLoC and have said that they are going to block it on their end. (Vivaldi/ZDNet)

Just a few weeks ago Google announced that they were turning off support for third-party cookies on the Chrome browser. This move obviously is going to change how companies, including Google, track users on the internet. So does that mean Google is going to stop tracking you? Of course not! Google is replacing third-party cookies with something called FLoC or Federated Learning of Cohorts.

What is FLoC or the Federated Learning of Cohorts?

FLoC is Google's alternative to third-party cookies and is based on machine learning. This will allow the browser, any browser, to anonymously study how users are browsing and then group them in ‘cohorts'. Following this, you will be served ads based on your cohort and not on your individual data. So, you are still going to be targeted with ads but in a more anonymous manner. 

Google claims that this will improve user privacy since this “federated learning” happens on the user's device and artificial intelligence-based learning involves sharing lesser user than what happens with third-party cookies. If something like this gets widely adopted by ad companies and services, it should “protect users” from tracking methods that are more intrusive than third-party cookies, like browser fingerprinting.

Which browsers are against it?

Privacy-focused browser DuckDuckGo, Brave and Vivaldi have all warned users against FLoC and have said that they are going to block it on their end.

Why are these browsers against FLoC?

DuckDuckGo has pointed out in a statement that as a Chrome user you will be “surprised” to learn that you have automatically been entered into Google's new tracking method. "It groups you based on your interests and demographics, derived from your browsing history, to enable creepy advertising and other content targeting without third-party cookies," DuckDuckGo said.

"After a short trial period, Google decided not to make this new tracking method a user choice and instead started automatically including millions in the scheme. If you're reading this in Chrome while logged in to a Google account, yes, that likely means you too, and if not now, then eventually," they added.

DuckDuckGo added that in response to Google automatically turning on FLoC, they have enhanced tracker blocking on their own Chrome extension to block all FLoC interactions on websites.

Brave Software, which offers open-source web browser Brave has also said they will block FloC and added that they have already disabled it o the Nightly version of both Brave for desktop and Android. They are now planning to roll out the changes into the stable versions of the browser in the coming days.

“The worst aspect of FLoC is that it materially harms user privacy, under the guise of being privacy-friendly. Others have already detailed many of the ways FLoC is privacy harming. We note here just three aspects of FLoC that are particularly harmful and concerning,” Brave CEO and co-founder Brendon Eich and senior privacy researcher Peter Snyder wrote in a blog post.

“Google's approach to determining whether a FLoC cohort is sensitive requires (in most cases) Google to record and collect that sensitive cohort in the first place! A system that determines whether a cohort is “sensitive” by recording how many people are in that sensitive cohort doesn't pass the laugh test,” Eich added.