As you know, Facebook has developed an entire network of advertisers outside of its core social network, which as a so-called third party monitors your activities on their websites and applications. So they collect data about habits, i.e. visits to specific sites and applications by users, and later those users can see certain advertisements that are similar to those they have already seen on specific sites.
But Facebook has announced that it is changing its policies and practices with such data, it would be said. Thus, the Facebook Off Activity tool was introduced, which allows users to have an insight into collected information and data from Facebook about habits, i.e. visits of users to certain sites outside the basic social network. How they claim in this way will increase the transparency of the information and data collected. It remains to be seen how this will work.