Oh yeah, I went on a date with someone I met online once. ONCE.
Never again. I'd rather die alone, at this point.
I've known a few characters like that, they're interesting but quite strange. Can't say I've dated any, but women on dates are not the only targets. I'm pretty sure these types feed on attention, and they're just as desperate to make male friends as they are to get into a female's pants. What really irks me is when they reveal their love of any form of Video Games. Generally, these types are "hardcore into Super Smash Bros." or "a purveyor of japanese romance games". They're the loud, completely socially inept stereotypes that make it feel weird to be a gamer in public. I'll be talking to my Bro Lab Partner, the guy who has only ever played Call of Duty: Black Ops II, when Outcast Guy comes waddling over. I'll be in the middle of recommending things Bro Gamer might enjoy, things that might open his eyes to new experiences and maybe even get him interested in new types of games, and here Outcast Guy is with "OH HAY GUYS! I HEARD YOU TALKING ABOUT GAMES AND NOW I'M GOING TO TELL YOU ALL ABOUT THE TIME I PLAYED ZELDA: WIND WAKER!"
There's also no way to talk to a female about games, lest this guy try to cut in with his 1337 Ski11z. I'll be talking to her, "Oh, you've played the whole Mass Effect Trilogy? That's really great! Did you go Renegade or Paragon? Who'd you leave on Virmire?" and before she can answer, sure enough, Outcast guy hears us from across the room and comes over with "OH HEY! MASS EFFECT!? MAN, THE ASARI ARE SO HOT! HAVE YOU EVER COSPLAYED? YOU SHOULD COSPLAY AS AN ASARI OR FEMSHEP OR SOMETHING!"
Cases like that, I don't even know how to handle them. Conversation's pretty much over at that point. Games are not a topic I'd like to touch with that female again, because I don't want to remind her of this guy, or accidentally bring him back around again. From there, it's damage control. How do you get this guy away from you without being a dick, and with the minimum emotional damage? He's nice, if completely inept. You don't want to hurt him, you might even discuss Zelda with him in a different place and time. But right then and there, you want that guy FAR away from you before he starts telling you about his mother, any weapons or odd collections he may have at home, any anime/manga he likes, or the medical problems of his pets. Many times, this guy becomes a social WMD. As soon as he hits, you're instantly vaporized. She's a shadow on the wall in the best case, and in the worst case, you might have to take the bullet and chat him up so that he doesn't pester her.
I had one guy who managed to do all of this without even directly talking to us, but that's a story for later.