With due consideration, and for relatively good reasons, I gave my 13 yo a Facebook account. It's not something I'd recommend generally, but the circumstances are atypical.
Of course we're "following him", but that's a weak monitoring measure. More importantly, he doesn't know his password and if he does a password reset he'll lose access.. That was a condition of giving him an account. I've also configured it so email notifications are copied to my personal email.
We'll see how it goes. I'm cautiously optimistic.
That is not to say I've changed my opinion of Facebook. Jesse Stay swears they're not Evil, but check out the default privacy settings that a new user gets (the default are all that matter, click to enlarge);
The access given to Facebook "apps" is particularly impressive. I don't see any evidence that FB has "reformed".
I flipped everything to a the same very secure settings I use. As usual in the troubled world of "Parental Controls" I ran into a glitch. Some settings changes require an https connection, and OS X Parental Controls can't manage most https connections (an increasingly serious problem). So to change his settings I had to use an account with more privileges. One side-effect is he can't change his preferences, which is not entirely unwanted.
I hope to update this post as I learn more ...