Tor is free software and an open network that protects user's internet use against traffic analysis by bouncing communications around a distributed network of relays run by volunteers all around the world.

TorBar makes contributing to the Tor network easy. It adds a menu bar item that allows you to run a Tor relay node (not an exit node) that uses the minimum amount of bandwidth (50kbps up/down) at the click of a button. It remembers and will only run the relay on networks you've specifically enabled it to run on.