1) The Internet never forgets. If you post something regretful in a fit of rage you can never take it back. You are not the same person you were ten years ago (even if you have the same name). Do you want to be judged today on how that person behaved back then? It is naive to think you won't be judged so.

2) There are some really batsh*t-crazy people in the world. I prefer to be somewhat isolated from them.

3) How do you verify a real name from a real-sounding name?

I would also like to see some evidence that "Real Name" = "better comments".