Dritz, joining Facebook for business reason. MAN, Business and Facebook are oxymoron. How can someone think even for a second that Facebook is a professional network! Really, what would company choose between sending mails to each other everyday or to use Facebook (which can disclose all their personal information).
Altogether, there are many stories of people loosing their jobs because of Facebook and not vice-versa.

As was said, Facebook is just a huge market place where they are selling personal information to the ads/apps that appears everywhere.
This is simply a way of controlling the population, inserting them in a bubble where they can only see what they want, talk with who they want, and feel comfortable sharing everything they know and are.
In a nutshell, it's like a zoo!