What is the law regarding pictures on usenet?

There is no clear legal definition in federal or state law as to what exactly constitutes a "lewd" or "lascivious" exhibition. These terms are to be interpreted according to "contemporary community standards." Defining the standards of a community where residents come from a wide variety of ethnic and cultural backgrounds, and where moving from place to place is commonplace so that the nature of a community is continually changing, has proved extremely challenging.