Back when I would chat I used a nickname that had "girl" tagged on it. I got a ton of PM's from guys. Some weren't trying to hit on me (obviously anyway) but most were. After awhile I changed my nickname to something that wasn't gender specific. The PM's cut down drastically.
Quite a few people here thought I was a guy at first. So I put a signature saying I was a woman
But I haven't been hit on yet.
Sniff, I must be losing my touch!