Google FLoC (Federated Learning of Cohorts)

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What Does Google FLoC (Federated Learning of Cohorts) Mean?

FLoC (Federated Learning of Cohorts) is an alternative to third-party cookies that Google rolled out to a small number of Chrome users beginning in 2021. According to Google, FLoC aims to provide users with additional online privacy, while still supporting the underlying economics of Google Adsense.


Instead of using third-party cookies to track individual users, FLoC creates cohorts composed of thousands of groups of internet users who have similar surfing habits so ads can be targeted accordingly. Google then uses machine learning algorithms to assign individual browsers to a cohort. FLoC periodically looks at the browser's history to see if a user's web habits have changed and adjusts cohort assignments accordingly.

Google is working to phase out its use of third-party cookies as part of the company’s promise to improve user privacy. (Safari and Firefox have already blocked third-party cookies by default.) As of mid-2021, all information about what cohort the browser is assigned to is kept local and does not get uploaded to Google servers.

First, second and third-party data comparison chartLearn the difference between first and third-party cookies.

Techopedia Explains Google FLoC (Federated Learning of Cohorts)

FLoC, which is expected to be 95% as effective as third-party cookies, originally launched to a small number of users in multiple countries around the world, including Australia, Brazil, India, Japan and the United States.

Concerns about FLoC

Small browser companies who have built their reputation on privacy (including Opera, VIvaldi and Brave) have announced they will not be implementing FLoC. Microsoft Edge, which is Chromium-based, is taking a wait-and-see approach while still continuing to work on a similar strategy called PARAKEET.

How to Opt Out of Google Chrome FLoC

Google's FLoC canary rollout is also controversial because the company has said it does not intend to apply the concept of cohorts to Google owned-and-operated properties. The issue in question here is whether or not Google considers Chrome to be an "owned-and-operated property." Should Google claim Chrome as its own, it would allow Google — and only Google — to view browser data at the individual-user level.

To find out if your Chrome browser is part of Google's canary-style incremental rollout, you can visit the website Am I FLoCed? Chrome users can also opt out of FLoC by disabling third party cookies in Chrome settings.


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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.