Most tools that help you surf anonymously do it by rerouting the data coming out of your computer, called traffic, so that it appears to be coming from somewhere else. Anonymous Surfing ($30; anonymizer.com) does this by shuttling all your traffic through its own servers. A free tool called Tor (tor.eff.org) uses a network of hundreds of servers, called nodes, and reroutes your traffic through several of them. To the sites you visit it will appear that you´re coming from the last node in the circuit. This also protects your traffic in transit. If an online snoop is watching your data, all he´ll see is that you´re moving between two nodes. He won´t know where you´re coming from or where you´re going.