To Block FLoC or not? Google’s new tracking technology

By Solomon Gifford

A lot of interest has been generated recently on the implications of Google’s new tracking technology – Federated Learning of Cohorts (FLoC).  In brief, Google is trying to reduce its dependency on cookies (or eliminate them) and instead allow the browser to assign each user tracked into an “interest cohort” – which is essentially a tag for a group of people that all share similar interests.  As a user browses the web, the browser summarizes all activity and assigns a cohort.   Advertisers are then able to target specific cohorts.

One of the biggest concerns related to FLoC is the potential to allow websites and advertisers to discriminate against specific types of users.  While Google has put a number of protections in place in advance of rollout, concern still exists that those protections could change or that they are insufficient for abuse.  Since the cohort can change every seven days based on recent activity, advertisers can begin creating a profile of an individual based on their changing profiles and target appropriately.  

Of course, there are also concerns that private profile information can also be leaked and used unethically.  Other websites could collect cohort information and provide discounts – or price increases – to specific groups of individuals.  Employers could ascertain that their employees are also students and deny them a promotion.   

The good news is that both individuals and site owners can opt out of FLoC. 

While we think that reducing the use of cookies and those annoying cookie popups will have a positive impact on end users, we also recommend that site owners consider opting their site out of FLoC if their site content could possibly compromise their users.    Some content management systems like Drupal or Joomla have gone so far to block FLoC completely from all sites using that technology, starting with Drupal 9.2 and Joomla, using an opt-in strategy instead.

For sites hosted with Contegix on the Contegix and BlackMesh platforms, disabling FLoC is simple – just submit a ticket and we’ll take care of the rest by updating apache, nginx, haproxy or the appropriate middeware to block FLoC.  For sites hosted elsewhere, contact us today for a free quote.

 • Chrome Developers: How to take part in the FLoC origin trial
 • GitHub: Federated Learning of Cohorts (FLoC)
 • Add Permissions-Policy header to block Google FLoC