"The Tor project is most famous as a tool that allows Internet
surfers to access websites privately and anonymously from within
the "onion router." Put simply, it works by passing your requests
to another node that acts as a middleman between you and a website,
which in turn passes the request onto other nodes, and so on. Every
step is encrypted except for the final exit node to the content
server connection, and the network is run almost entirely by
volunteers.
"The tool is often recommended by privacy advocates and rights
groups when educating users about how to gain free access to
information from countries that restrict or censor Internet access,
such as China, Saudi Arabia, and Iran. In fact, both the Electronic
Frontier Foundation and Citizen Lab have endorsed the use of Tor so
that users can retain their online privacy while surfing, although
the network has gotten somewhat of a bad rap for allegedly enabling
the trafficking of child porn and anonymous bomb threats. (The
project was previously funded by the EFF but has since broken
off.)"