That was my experience on OKC as well. When I put an awesome picture and profile up and just hung back and waited, I got several emails and I'd say maybe one or two of them were from guys I'd actually respond back to i.e. not messages that simply said "Hi" or "Ur cool" (I mean, what do I do with that?) Quite a few messages were also pretty sexually aggressive/suggestive, which seems to be common on the free sites and is not my experience alone; friends of mine have also had this experience.

I wouldn't be too quick to feel that it's something wrong with you. Many guys (not ALL of them...but a fair number) on the free sites aren't looking for a long term, get to know you slowly kinda thing. So opening with a casual "Hey, I'm into your interests" convo isn't going to hook them. Which is fine, because it sounds like those aren't the guys you want anyway. You're alright...just keep fishing.