typical online dater is either a fabulist, a narcissist, or simply re- sistant to the meaning of "average." (Or perhaps they are all just real- ists: as any real-estate agent knows, the typical house isnt "charming" or "fantastic," but unless you say it is, no one will even bother to take a look.) Twenty-eight percent of the women on the site said they were blond, a number far beyond the national average, which indicates a lot of dyeing, or lying, or both. Some users, meanwhile, were bracingly honest. Eight percent of the men-about 1 in every 12-conceded that they were married, with half of these 8 percent reporting that they were "happily mar- ried." But the fact that they were honest doesnt mean they were rash. Of the 258 "happily married" men in the sample, only 9 chose to post a picture of themselves. The reward of gaining a mistress was evi- dently outweighed by the risk of having your wife discover your per- sonal ad. ("And what were you doing on that website?" the husband might bluster, undoubtedly to little avail.)   Of the many ways to fail on a dating website, not posting a photo of yourself is perhaps the most certain. (Not that the photo necessar- ily is a photo of yourself; it may well be some better-looking stranger, but such deception would obviously backfire in time.) A man who does not include his photo gets only one-fourth the volume of e-mail response of a man who does; a woman who doesnt include her photo gets only one-sixth the response. A low-income, poorly educated, un- happily employed, not-very-attractive, slightly overweight, and bald- ing man who posts his photo stands a better chance of gleaning some e-mails than a man who says he makes $200,000 and is deadly hand- some but doesnt post a photo. There are plenty of reasons someone might not post a photo-hes technically challenged or is ashamed of being spotted by friends or is just plain unattractive-but as in the case of a brand-new car with a for-sale sign, prospective customers will assume hes got something seriously wrong under the hood.