Not content with monitoring the movements of its own users, the largest social network in the world is building secret files on the activities of billions of people.
Mark Zuckerburg’s company says that is uses this information to target adverts and content based on your preferences, as well as for security purposes.
Facebook account holders are able to download a copy of the file kept on them, which contains detailed records of their activities while logged in.
Source: Facebook keep creepy secret files on every internet user | Daily Mail Online
Facebook, an NSA buddy, collects all this data in order to better pitch propaganda a.k.a. advertising messages to you.