How Facebook Is Selling Your Timeline to Advertisers 15 years ago
Exactly. When someone throws the old (yes, old) "Facebook monetizes the info that you post" argument in my face, the only thing I understand is that he's either new to Facebook and skipped the terms or... I don't know.
Bottom line is, Google did the same thing more or less when they introduced Google instant (reducing "I feel lucky" usage to serve more links) and, this might sound harsh, both are companies aim to make money while at the same time improve your user experience by serving targeted ads.
Seriously, it's nothing ground-breaking that no one knows.