Five things you need to know about the end of Google’s third party cookies and the dawn of FLoC

By Kimberley Loynes, 16 November 2021

Cookies are small text files stored on a user’s device via their web browser. At one level, they can provide useful services such as remembering settings we applied when visiting a website, that are then reapplied when we next visit. However, cookies to support advertising, particularly from organisations unrelated to the website we visit (third party cookies) have exploded in use in recent years. 

  1. Google is stopping the use of third party cookies in 2022 which will significantly impact digital marketing. Third-party cookies are digital user IDs which are set by a third-party platform or technology provider on the website. Third-party cookies have been used to track website visitors, improve experience, and collect data to target ads to the desired audience. A big advantage of third-party cookies for advertisers was that they tracked what users were browsing throughout the entire web and not just on the site on which these cookies had been installed. This cancellation comes as distrust of third-party cookies has increased in recent years. 

  2. As a solution to the end of third party cookies, Google is currently working on FLoC (Federated Learning of Cohorts). The FLoC tracks which websites users have visited and combines the users into groups of interests that can be targeted with ads.

  3. Google is running a trial version of FLoC right now with Chrome users and you can find out if you are one of these testers here: If you have been assigned a FLoC ID, it means that your browser has processed your browsing history and assigned you to a group of “a few thousand” similar users. 

  4. The difference between this and third party cookies is that targeting is based not on individual IDs but on the groups to which they belong. The group ID prevents tracking an individual user between websites. 

  5.  Google states that preliminary data shows that using these cohorts leads to similar results for them and that advertisers can expect to see “at least 95% of the conversions per dollar spent when compared to cookie-based advertising.”

FLoC is still in the trial phase and we will have to watch this space to see how it progresses. Google plans to trial FLoC with advertisers in the coming months. 

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