Voices of Dissent

Free-speech advocates once dreamed that the Internet might make it impossible for repressive governments to control information and stifle dissent. But while the Internet has given dissidents more ways to communicate with some privacy, authoritarian regimes have still found ways to censor websites, to monitor e-mail and to track down and jail online offenders. Still, in this game of electronic cat and mouse, the methods for evading roadblocks are evolving, and in Vietnam pro-democracy activists have hit upon a useful tool: Internet telephony, or Voice Over Internet Protocol (VoIP).

This technology, which allows users to make digital...