Here is a short animated video about what Facebook is for.
I find both funny and creepy the definition of Facebook as "a massively multi-player online role-playing game (funny part) whose objective is to collect "friends" (creepy part)".
Watching it made me think:
1) Will it ever be possible to think even at real life as a "multi-player role-playing game"?
2) The list of "People From The Past": if some people stopped communicating with someone on purpose (nothing in common), why having them as 'friends'? The fact that being on Facebook is the only point in common looks so sad.