Robert Arena, a political Internet expert with Presage Internet Campaigns in Alexandria, Virginia, says the Internet helps fighters for tolerance by exposing the activities of previously shadowy groups.

ECONOMIST: The Internet

Tim Wu, an internet expert at Columbia Law School in New York, says sites like YouTube face huge problems if they wield editorial power, and huge problems if they don't.

ECONOMIST: Censorship and the internet

Bruce Schneier, an internet-security expert, thinks it is a bit like worrying about spammers stealing a copy of the telephone directory.

ECONOMIST: A large theft of company e-mail lists causes controversy