The online dating site OKCupid has a blog where they post analyses of the tons of data they collect, and it's really fascinating.
For instance the attractiveness of woman on OKCupid, as judged by the men on OKCupid, is a symmetrical bell curve. In other words, half the women are better-than-medium looking and half are worse-than-medium looking. But OKCupid's women rate 80% of OKCupid's guys as worse-than-medium looking! Even more interesting: while men are much more likely to send messages to the most attractive women, women are much more likely to send messages to men who are slightly less-than-average looking.
As you can see from the gray line, women rate an incredible 80% of guys as worse-looking than medium. Very harsh. On the other hand, when it comes to actual messaging, women shift their expectations only just slightly ahead of the curve, which is a healthier pattern than guys' pursuing the all-but-unattainable. But with the basic ratings so out-of-whack, the two curves together suggest some strange possibilities for the female thought process, the most salient of which is that the average-looking woman has convinced herself that the vast majority of males aren't good enough for her, but she then goes right out and messages them anyway.
Your Looks and Your Inbox (Thanks, Vann!)