My boyfriend and I met on OKCupid this summer and we're very happy together. He was one of the first people to send me a message and I was already half-seduced by his brain by the time I'd finished reading the first message he wrote me.
We weren't in the same city at the time because I'd gone home over the summer to live with my parents -- it sounds kind of naive in retrospect, but I didn't really think that I was going to meet anyone I liked even remotely. For better or for worse, I'm quite picky. So because of the distance thing, we ended up talking to each other online for two months before we met. It was kind of Victorian in a way; we wrote each other letters for more than a month before eventually progressing to IM. Waiting for his responses was agony... partially because I'm impatient, but also because I think my generation is very used to instantaneous communication.
Anyway, we went on our first date the first night that I came back and we've been very happy together for the last seven months. I have lots of embarrassing posts lurking around the forum to prove it. He's my best friend.
So ultimately, I'm pro-online dating, especially for introverts.