Some will give up everything for very little-the presidency, perhaps, in exchange for a glimpse of thong. But that's the definition of desire, isn't it? An inexplicable passion that defies reason and overthrows us? Type "Lolita" to search the Web (use, say, Excite), and a would-be Humbert quickly finds the word is now a brand name. Lolita is a book; a movie; a band (My Lolita); a decadent chocolate dessert (Sweet Lolita); an orca whale (the oldest in captivity, it was snagged in Puget Sound); and a line of clothes from France's upscale Agnes b., which promotes its "Lolita" wear with an arty shot of a young woman bending over in the half-light, an innocent daisy poking out from behind her ear. But with a small "l," the name is a code word accessing a multiplicity of X-rated desires. If you dig, you will undoubtedly unearth out-and-out kiddie porn, but if you merely troll the surface, you'll find a mainstream recognition that men (and some women) are powerfully turned on by the blending of sexual awakening and innocence: younglips.com, japanesegirls.com, lolitagirls.com, pinkteens.com. For the most part, they offer photographs of "barely legal," flat-chested women ("A-cup Girls!"), dressed to suggest jailbait (plaidskirts.com). There are laundry lists of subfetishes that can be had for your credit-card number: teens, Asian babes, lesbian Lolitas, raised skirts, spanking, fingers, and, most mysterious, "puffies" and "plushies." A puffy turns out to be an adolescent girl with young, puffy nipples (your choice, of course-click here for puffy and here for erect). Plushies are stuffed animals, the kind that cover little girls' bedspreads; some people, it turns out, like pictures of teens with teddy bears. Other folks make love with their plushies and modify them accordingly. That Beanie Baby? You really don't know where it's been.The Web offers privacy. "Your wife will never know!" is the billing promise of one site. But someone will. Certainly the pornographer and his database operator. Under the guise of just-between-us secrecy, this seductive world shows us its thong. It's only a matter of time before a Humbert will be tempted to return and give up everything for a stranger.