The very notion that there is any privacy online should die quickly when you see the latest article on the matter from the Wall Street Journal which shows many apps on Facebook are not only sharing lots of personal information about you they are actively piecing together person profiles on users and selling this information to others.
Of special note in the list companies conducting such behavior and in this case – transmitting Facebook IDs to dozens of other firms is RapLeaf – but the company says they did it by accident.