Are Free Social Sites Really Free?

Most likely you have a Facebook account and love the fact that it's a free site... But is it really free? After all, someone has to pay all those people to work behind the scenes. Who's paying for all the upkeep and changes to Facebook? You are! All the information you willingly and unknowingly give away to advertisers - And they post their ads on your wall, your friends walls, and also on the sidelines. How do you feel about that?