That's interesting, I have tried using OKCupid for dating, but it seems like all of my matches are women I might be interested in platonically, but not for dating.
It could be that OKC has developed a very good system for meeting new friends, but not necessarily for dating.
Out of curiosity, what qualities are desirable in a female friend that aren't in one you would date (aside from the obvious like "she's married" or "she's only interested in dating the wrong gender")
I'm guessing that it's the other way around; there are qualities that are desirable in a person GP would date that are not found in people who would still be great friends.
It could be that OKC has developed a very good system for meeting new friends, but not necessarily for dating.