My soon 12 yr old asked me if she could start a facebook page so she could play the games. I made the page, turned everything on private, know the password, I upload the pictures I allow her to have and I am the one that can accept her friend requests. She is limited to the amount of time she allowed to spend on there. Usually in one week she is on there a total of 2 or 3 hours in 7 days. I do allow her to use the chat feature as it only has the people we have allowed on her friends list.
I have had friends of mine try to friend her due to being in their "suggestions" and I have politely told them that it is her site for her to play the games and I only allow her to have certain individuals on there. Everyone seems to accept my explanation to them. It is really nice to use for family members that live far away.
I also told her that any messages that are received and sent will be viewed by me, so that I know what is going on. Sure it might be a little overbearing, but she needs to respect what I ask of her and so far she is being very responsible about it. She knows that if something goes wrong the pages goes away.
When she turns 13, I will continue doing this too and slowly give her more control over it unless I see things questionable!