Here is a simple rule to avoid making an ass out of yourself over things you have sent/said/participated in on the internet:
Bulletin Board. Never post anything that you don't want a lot of people to see.
It is that easy. Yes, I know it is a bulletin board that is stuffed to overflowing like a flyposting board at the Edinburgh Fringe, but seriously, there are people who will grab a ladder and peel back the layers looking for stuff. So if you don't want it seen, keep it in your pants.