Facebook probably collects more data about your internet use than the NSA does.
yes but so far Facebook (and Google which does the same thing) isn't in a position to arrest you for sending emails of kitties to enemy countries.
Even more to the point, to quote from the company's Data Usage Policy:
We also put together data from the information we already have about you and your friends. For example, we may put together data about you to determine which friends we should show you in your News Feed or suggest you tag in the photos you post. We may put together your current city with GPS and other location information we have about you to, for example, tell you and your friends about people or events nearby, or offer deals to you that you might be interested in. We may also put together data about you to serve you ads that might be more relevant to you.
On the other hand, why does Lolo get emails from Obama's fund raising arm, when he is a Republican? Maybe because I use his email address for our facebook page?