Well, that's a very simplistic view, but I'm not up for the challenge presently. If all Facebook users were legal adults, you'd be on less shaky ground.

However, I was thinking more about private messages and chats, tracking cookies, etc. Also pernicious: being tagged in other people's content.

Tying a real name to private data can have repercussions, even for responsible law abiding adults -- especially when the data is archived indefinitely, in one convenient central location.