My first roleplay was tabletop RPGs with my older brothers friends - old school Dungeons and Dragons. They kept trying to sleep with NPCs and eventually with my character. Then I started "writing" with two of his friends, which turned into sexual roleplays, which turned into assumptions that I wanted to do all that stuff in real life, etc.
My first online one-on-one roleplay was probably on... Yahoo? either than or IRC. Then I moved onto IMVU, which was fun for a while, and tried Second Life but my computer was old and didn't run it well. Then I floated around trying to find other site. Elliquiy and Red Light District were my most recent, although Red Light closed.
I think even my old tabletop days, my characters were more sexual than anyone else.