Anybody that was around years ago probably already knows what mine is all about.
Obviously it's a stop sign, but there's a bit more to it.
Basically, I used to run the IRC chatroom #srb2fun. Back then, I ruled with a bit of an iron fist, mainly out of necessity at the time since we were having a really bad problem with stupid people. I tended to have a very short fuse for dealing with people, giving them a single warning by simply saying "Stop", and kicking/banning them if they continued with whatever was irritating me. It turned into a small in-joke in the community, and I can't remember having any other avatar at the time, so I decided to humor it and make my avatar a stop sign. I haven't updated it since.