Tor is a technology that allows users to browse the web and access online services without revealing their identities or anonymously. The Tor network consists of thousands of servers located all over the world which are run by volunteers seeking to bolster privacy rights.

A Tor-based browser allows users to browse the web by automatically bouncing off their online communication over a number of Tor servers before reaching their destination. The process makes it almost impossible for anyone to trace the traffic back to the original user. Even the NSA has struggled to unmask Tor users.

The technology allows the creation of hidden services, websites that use the Tor network to hide their physical location. As a result, Tor has allowed the creation of websites devoted to illegal activities that are difficult for authorities to trace and shut down.

Surprisingly, Tor was created with financial support from the US government, which wanted to promote the free flow of information. Government support for Tor has continued in recent years as part of the State Department's internet freedom agenda, which seeks to help people in repressive regimes gain access to information censored by their governments.

While Tor has many illicit uses, it also has a lot of legitimate ones. For example, Facebook recently announced a version of its website that can be accessed over the Tor network, which will make it easier to access the site from countries that restrict the service, such as China and Iran.