InfoAnarchy -- All WikiWebs allow anonymous publishing: The InfoAnarchy Wiki is just one example of the ones dedicated to free-speech.
InvisiBlog -- True anonymous blogging
Konspire2b -- Peer-to-peer publishing system
Freenet -- Distributed anonymous free speech
"I worry about my child and the Internet all the time, even though she's too young to have logged on yet. Here's what I worry about. I worry that 10 or 15 years from now, she will come to me and say 'Daddy, where were you when they took freedom of the press away from the Internet?'"
--Mike Godwin, Electronic Frontier Foundation
