The first generation to grow up with the Internet and all it has wrought in the cultural mainstream is beginning to come of age. It is a generation for whom 900 numbers and scrambled scraps of flesh on the Spice channel have given way, in a few short years, to bulk e-mail ads for the Paris Hilton sex tapes and porn subplots on "The O.C." It is a generation in which sexual frankness has become a permanent feature of the landscape, with uncertain long-term implications. By definition, pornography is sexual material that is so beyond the pale as to be...