WikiLeaks:- underground

WikiLeaks is also reported to have siphoned off over a million documents online using Tor (also known as 'The Onion Router') -- a privacy tool that lets users navigate and send documents without the fear of being traced.

A Tor network uses around 1,000 volunteer servers around the world. To transmit a document, a whistleblower downloads the software (called Tor client) and uses it to insert the document into the Tor network.

The whistleblower site reportedly hosts its main servers in Sweden (Sweden has clear legal protections for the confidentiality of journalistic sources, though the application of these protections to WikiLeaks contributors has not been tested in court) with backup servers in other jurisdictions.

Its hosting provider, PRQ, was originally founded by one of the creators of the controversial file-sharing information site, Pirate Bay, as a free-speech friendly Internet service provider.