Federated Learning of Cohorts (FLoC) proposes a new way for businesses to reach people with relevant content and ads. We explore what this could mean and why we are giving you the choice as to whether to use it or not.

FLoC is clustering large groups of people with similar interests. This approach effectively hides individuals “in the crowd” and uses on-device processing to keep a person’s web history private on the browser.

In short it allows interest-based advertising on the web. Instead of the current cookie based tracking, you’ll be associated with a “cohort,” a group of users sufficiently large enough to make you at least semi-anonymous to the companies targeting you.
But its business lead, as Google says, a new way for businesses to reach people. Beside no other browser vendor has signaled its intention to support FLoC.

Many argue that if we don't want to be followed as private individuals then we have the right to not be followed. If personalised adverts are designed to make us buy more with less advertising budget spent then is that in the person's interest, the environment's interest or the business that's trying to sell via the web?

Why Floc, well part of the name derives from the bird themed technical standards: PIGIN, TURTLEDOVE, SPARROW, SWAN, SPURFOWL, PELICAN, PARROT all designed to replace functions currently done by cookies. FLoC is part of a suite intended to bring targeted ads into a privacy-preserving future, sharing new information with advertisers.

There are concerns about some of the technologies it uses to add you to the cohorts. Fingerprinting involves gathering pieces of information from a users browser to create a unique, stable identifier.

Another issue is Cross-context exposure
The technology will share new personal data with trackers who can already identify users. For FLoC to be useful to advertisers, a user’s cohort will necessarily reveal information about their behavior.
This means every site you visit will have a good idea about what kind of person you are on first contact, without having to do the work of tracking you across the web.
If you visit a site to buy a jumper they will have access to your cohort identifying number. This could also give them your political thinking or reveal that you are also in certain defined medical groups. There is nothing to stop these groups being backward engineered and your movement between the cohorts will reveal a lot about you over time.

Joomla! along with other content management systems and web frameworks are planning to block FLoC and this comes into effect with Joomla! 3.9.27
You can find the setting in Global configuration on the Site tab in the Site Settings area.
Block FLoC Yes/No and the default setting will be Yes

Further reading

• https://en.wikipedia.org/wiki/Federated_Learning_of_Cohorts
• https://spreadprivacy.com/block-floc-with-duckduckgo/
• https://www.eff.org/deeplinks/2021/03/googles-floc-terrible-idea