This article discusses falling ad revenue for social networking sites. That probably explains why the ads on FaceBook seem sleazier lately. About every other time I log in, I get pummeled with an ad to meet "sexy singles in Blacksburg," along with what is supposed to be an example of a "sexy single" in a bikini. Bottom fishing ads like this one may be helping to pay the bills on these sites, but as the sleaze factor goes up, more parents are going to start declaring the sites off-limits to their kids.