What do these symbols mean?

At the bottom of the home page of the forums, in the 'What's Going On' box... why are there usually symbols next to users names, I know why there is a difference in colour between normal members, mods and admins but why are there these symbols... For example I've just seen that all of a sudden I have * next to my name, and Bazza` has a +...



edit: So I know why I had the * next to my name, because I was in invisible mode, but why does Bazza` have a +?

Sorry if this is a stupid question but it's been bugging me for some time now...