How does it work for a minor using Facebook? Are their accounts public by default? Can they friend and be friend-requested by anybody? Are they linked to their parent accounts somehow so that parents can monitor or approve requests? When they become an adult, is all of the data/content/history going to stay with the account? So when they are 20, friends can see what they wrote when they were 12 if they dig into their history?

(I am not very familiar with Facebook but I do have two young kids who will probably start wanting it soon)