"Yet while anonymity offers a potential bulwark against surveillance, for those who do not wish to be watched, it has also helped in the development of that part of the online world known as the dark web.
Sites on the dark web like Silk Road have used Tor technology to hide their location and yet still be available to users who wish to visit them.
The dark web has now become a focus for law enforcement officers who believe it is facilitating a variety of illegal activities including financial crime and child abuse."
(Mike Radford, 3 September 2014, BBC News)
Fig.1 "Inside the Dark Web" 2014, television programme, BBC Two – Horizon, Series 51, Episode 4, first broadcast: 3 September 2014.
"Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built–in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy.
Individuals use Tor to keep websites from tracking them and their family members, or to connect to news sites, instant messaging services, or the like when these are blocked by their local Internet providers. Tor's hidden services let users publish web sites and other services without needing to reveal the location of the site. Individuals also use Tor for socially sensitive communication: chat rooms and web forums for rape and abuse survivors, or people with illnesses.
Journalists use Tor to communicate more safely with whistleblowers and dissidents. Non–governmental organizations (NGOs) use Tor to allow their workers to connect to their home website while they're in a foreign country, without notifying everybody nearby that they're working with that organization.
Groups such as Indymedia recommend Tor for safeguarding their members' online privacy and security. Activist groups like the Electronic Frontier Foundation (EFF) recommend Tor as a mechanism for maintaining civil liberties online."
(The Tor Project, Inc.)