Previous case report:
Notably, Facebook servers keeps eye on the user data, the apps used by the users and the websites visited by them to provide relevant advertisement on their social page. Some of the privacy firm thinks this is where the user data leaks through the Facebook and can be of great concern for security. Earlier, a report filed at Federal Trade Commission revealed the fact, However, Facebook proved the security for user data to be sufficient at an independent audit.
The way Facebook is dealing with this: