The social function of the Internet has changed dramatically in recent years. What was, until recently, a supplement to other channels of information and communication has become increasingly a basic requirement of social and economic inclusion. Educational systems, employers, and government agencies at all levels have shifted services online—and are pushing rapidly to do more.

Advocates of online child protection and freedom of expression share a deep-seated belief in the importance of protecting basic human rights. Yet these beliefs are often clouded by perceived (and real) opposition in the actual practice of law, policy, and regulation. This has restricted the policy options available for dealing with threats to both child...