doing internet dating myself recently and MAN is it emotionally draining. I send 50+ mails, I get 1-2 replies, one of those is the usual "OMG cut and paste HOW DARE YOU!!!!!!" (my messages aren't even cut and paste, and man the way they react, is cut and paste == rape?), and the other turns out good but at some point usually after a few emails, quit replying. On a rare few occasions I get to the next level 90% they posted a pic of someone else, or are just a plainly unpleasant person(one I walked out on when she found out I'm into hiphop calling black people monkeys). So here's what I think is wrong.
Women: In normal society women have one or 2 guys approach them at a time, in online they're getting 20+ messages. This inflates their egos and makes them think they're more than their net worth(I hate saying that this way but I can't find another word), they begin to build this list of a perfect guy which they hold out for which is WAY unrealistic(I noted alot of girls have been on these things for years never even dating a guy).
Men: They realize this "game" and begin to play it, this isn't the standard "man women" game its a sleeze game. So many girls I've talked to ended up dating a married guy with kids, or met someone who wasn't even their pics. These guys know the right words/pics/etc. since for them they don't want to meet someone, they want to seduce someone.
In the end both sides get pissed off at one another, and no one moves forward. But who wins? The dating sites! They don't want you to find someone, they want your money!