Facebook is settling with the FTC over charges that they promised that customers data would be kept private and then repeatedly allowing it to be sold and shared publicly. There were no fines or penalties over this, they have gotten off scot free with the data mining of users data. According to the Federal Trade Commission, in December 2009, Facebook changed the privacy settings on their website so that certain information they designated as private – such as their Friends List – was actually made public and easily accessible. The users of Facebook were not warned about these changes and no approval was sought in advance of these changes being implemented at all. The worst thing is that all of those Facebook apps and games that you sign up for and they demand access to your data, but they were mining far more data than they let on, sending all kinds of data from users to god knows where. Sure use Facebook if you want, but be careful and do not sign up for those pointless games and other crap that the website has aplenty.
Facebook is very good for keeping up with updates from your favourite websites and friends, but you need to be careful what you share on that website as the sole purpose is to use customers data for advertising and building databases about users.