According to the group Europe vs. Facebook, which has made numerous complaints about the social network's privacy violations, Facebook is not only hosting enormous amounts of personal data, it's processing all that data for its own purposes--purposes that are not, and have never been, made clear to the user, or that the user has been given a chance to consent to or reject. But if you want to find out exactly what personal data Facebook has compiled about you and what they're doing with it, Facebook says, "Fuck you, plebes, we're not telling because it could reveal our trade secrets!"
I'm so glad I dumped these creeps when I did, but who knows what information they still have on file about me, and what they're doing with it? We already know they're handing it over to the government. Hope I didn't accidentally click a link to an opposition website!