The girl I talk to on Skype I met when my crazy bat of an online fling (who herself I met completely randomly in a one-in-a-million shot) asked me to keep an eye on her because she didn't trust her.
I found out that my target was much more interesting, intelligent, adult, and sane than the fling, and started to gravitate towards her. The fling thing disintegrated like it was destined to, and after two years of some tumult and a six month silent spell due to her being threatened by her now ex, plans are being made for her to come down from Canada to visit after the holidays. Neither of us can wait... in a "more-than-friends" way.
It's obviously too early to tell how it'll go down, but this stuff can happen any time, anywhere, any place. The internet is the new bar, only you have a much wider group of people and thus much better chances. I see no problem with dating sites; in fact, I'd say your chances are greater there than cruising a bar or club or really anywhere else.