Tried online dating off and on (fun at first then tired, take a break, return) and met some cool girls, and some not-so-cool girls. So really, online dating is no different than bumping into someone offline. You might find a spark or you might not. IMHO reading someone's profile (text on a screen) is worthless, you must meet in person to see what's what.
Only one real horror story so far: Craziest one was a girl who kept sending messages over and over, I was busy and couldn't meet for a few days. Finally meet, go get some food except she goes outside the restaurant and talks on her cell phone for 15 minutes. Hmmm. We leave afterwards, she says she wants me to type in an address into my GPS so I can drive her to go look at someone's house, but not go inside.
I said "uhhhh, no this silliness is over" and she got even more crazy weird after that, I made it to about a mile from her house before I flew off the handle, pulled over to the side of the road and said "get out, walk home."
(actually I kept looking around for a camera crew, thinking it might be one of those prank shows).