All requests you make through the network are bounced around inside for a while, and then exit the network at a random point and hit your destination. What basically happens is that you connect to the Tor network (Opens in a new window) via an encrypted connection.

That way compromised nodes can’t be used to monitor traffic. Traffic on the internet is a series of hops from router to router and network to network, and in Tor each network node has only the name of the relay it was handed the information from and the relay it handed the information to - so a full path of the traffic destination is never known. Tor, in case you don't keep up with internet security and obscurity, is a network of nodes that randomize your path through the internet, making it harder to track what sites and services you use. On October 29-30 in Sao Paulo, Brazil, the Hackers to Hackers Conference will occur, and one of its presentations will be about how the Tor anonymizing network was compromised by French researchers.

How to use tor browser safely