If you have pretty solid social proof, and pictures where you're shown being active, interesting, and have a few pictures with ladies around you, i could see it being beneficial. not a monsterous add to your arsenal, but a nice aid to your game.
I however, have two circles. My social circle, and then girls I'm chasing. I don't want those worlds to collide, and i know you can combat that with all the privacy settings and stuff but it's just easier to keep them seperate by not being on facebook
also, whether people want to admit it or not, mystery is a great seduction weapon. both sexes fall victim to it. there's just something sexy about not knowing everything about a person. it's interesting.
i also don't want to be so readily available. my generation *****s themselves around like they're faux celebrities but i refuse to play a part in that.
all i have is a number, that's the only way you can reach me