Mine has always been that way, I'm pretty savy when it comes to forums.. it's a setting in your User CP. Just set your account to "Invisible" and you'll show up as "Offline"
Well, on computer/technology type forums you don't do that. You're supposed to be there to help people and assist in their "problems" banning them because their a lame-o is a bit out of the question. Otherwise you wouldn't have any visitors.