Manny from Miami is not quite the sensitive single man he says he is. He is married with a kid, no less, and "he sleeps with women everywhere," according to his anonymous former girlfriend in a posting on DontDateHimGirl.com.

While many women find the Web sites amusing and sometimes helpful, they have enraged men, guilty or not, some of whom send e-mail messages or call the posted phone numbers to have their names and photographs taken down. They argue that the Web sites are biased and damaging, particularly if the story being told is false. And while the women remain anonymous, the men are offered up in full detail.

ManHaters.com, also known as WomanSavers.com, which features a drawing of a woman dressed in red, carrying a pitchfork and sprouting tiny horns, has a questionnaire that generates a rating of a man as good or bad from zero to 122; most men end up in the muddled middle. The multiple-choice questionnaire allows women to check off descriptive statements ranging from "stinks, has body odor, bad breath and doesn't care" to "He has the perfect balance of humility and confidence."

TrueDater.com is among the sites geared to online daters of both sexes and the untruths they tell behind the Internet's wall of virtual anonymity. The site can warn a woman that the purported 6-foot-4 Wall Street stockbroker with bulging pectorals is really a baldish, 5-foot-10 Wall Street Journal deliveryman with man breasts. Or it can alert men that a supposedly unmarried woman with the dimensions of a lingerie model is actually a married woman who hopes to achieve those dimensions with a little help and a lot of money.

Users post the nickname that the person in question uses on an online dating service like Match.com, and warn that the posted profile is misleading. A click of the mouse can send the curious to the person's profile page. Not all the news is negative. People who tell the truth are flagged approvingly as "true daters."