Introduction to the Darknet – A Free Course

The Darknet is a component of the Deep Web that is shielded from casual web surfing by systems such as TOR and Freenet.

When speaking of sites on the Darknet people generally are talking about TOR Services. TOR Services allow you to create your own webserver and have it accessible only from users of TOR. TOR Services are not routable on the standard Internet.

The key components of the Darknet are:
Uses standard Internet Technologies
Requires a Special Client to Access the Network
Anonymity for both Client and Server is maintained