Robert Scoble

Unfriend people who do not post to Facebook or engage with anyone else. You'll find your posts start getting reach they never did before. Why? Facebook only releases your posts to a few people at first and watches what they do with it.

Every time you log in to Facebook, every time you click on your News Feed, every time you Like a photo, every time you send anything via Messenger, you add another data point to the galaxy they already have regarding you and your behavior.