Freenet is free software which lets you publish and obtain information on the Internet without fear of censorship. To achieve this freedom, the network is entirely decentralized and publishers and consumers of information are anonymous. Without anonymity there can never be true freedom of speech, and without decentralization the network will be vulnerable to attack.
The network can be used in a number of different ways and isn’t restricted to just sharing files like other peer-to-peer networks. It acts more like an Internet within an Internet.
Download: Freenet 0.7 Windows NT/2000/XP, Mac OS X, Unix, and Linux