This x1000. It all depends on how smart the kid is. My folks taught me well at 12 and I had no problems whatsoever.
I would like to point out that nothing in the first quoted post says anything about MySpace, and wasn't even in text message form.
I don't mind 14 year olds using facebook. Of course, it's not that good of an idea. But if facebook was, and i had internets when i was 14, i would probably get it after some time. My parents recently got facebook, and my sister used it to play games. She is 8 and my parents made her her own facebook acount, just to play games like farmville and so on. I don't like it... But if i had a cat. Hell, i'd give him a facebook.