These days you're going to find the same types of people (everyone!) online as you do in the real world. Gone are the days when being online automatically made you a 1) nerd, 2) recluse, 3) weirdo, 4) all of the above. ;-)
I've met a few guys this way. I dated two for a while (over a year each), a few were hook ups, and a few became acquaintances. No horror stories to report.
That said, I don't think meeting online is necessarily a good thing. It's 2-dimensional. There's no chemistry, no body language, no locking eyes across the bar, no nervous butterflies as you approach him or he approaches you, etc. In my mind, that's important, vital even.
Online we reduce others to a checklist of desired traits while working to "market" ourselves most effectively. Is this really a good thing? I think manners have suffered greatly since the Internet boomed. People are rude in email, rude in chat, and hunting for your mate online really encourages you to view people in a somewhat inhuman way.
Of course being online isn't all bad. ;-) It's a great way to get answers, debate ideas with like-minded people, etc. But I'm not so sure it's the healthiest (mentally speaking) means of establishing friendships or deep personal relationships.