As the father of four twenty--somethings I stop-ped worrying about what they were doing on the internet long ago (and started worrying about other things, such as whether one of them should sign up for a stint in Baghdad).

But for the parents of younger children, the web's range of content poses a dilemma. It is an unparalleled research and educational resource. But it can also be scary and even dangerous for unsupervised children, who seem to have a knack for discovering inappropriate content.