On chat forums/boards these are things that are usually found under the main messege. Usually they eaither provide a link to some place, list a current goal, or say a witty phrase. Usually seperated from the main messege with a series of ----.
> 1. I was scanning over the posts to my forum and I saw the funniest siggys in the world!
> 2. (There usually in this format)
> -Long boring messege no one cares about-
> ---------------------------------
> -siggy with something funny in it like, 'if abuse is illagal, was is there school?'