Usenet was created as a combination of a huge mailing list and a giant forum.
Imagine yourself sending a joke to a close circle of friends, while they sending it to their circle of friends until eventually, your picture will reach everyone on the network. Now, in Usenet, the circle of friends is much wider and you also can classify your joke to be a part of the "jokes" section, so only people who interested in jokes will receive it.
The Usenet was rapidly developing, and soon you could also send a file, like a picture of your dog, to this large community, and after a while, this picture would spread all over the Usenet and everyone would be able to see your dog. (Now,Isn't it nice? :)) So that is how the
alt.binaries newsgroup (a Usenet "section") was born and soon after has been flooded with lots of shared binary content (movies, music, pictures and software)
Today, most of the Usenet is on the WWW and so are those hundreeds of Terabytes of this precious binary data.

To enter Usenet you must have an appropriate client (The easiest to get, comes with Windows -
Microsoft Outlook Express) and a Usenet ISP. Up until recently, downloading files from Usenet network was pretty slow and uncomfortable, since files took time to spread to all the servers. But now, new high speed clients and servers have appeared. And with high bandwidth and stability, they allow us to search and download Terabytes of data. Most of these servers, however, are not free.
But some of them, such as
UseNext.com, allows to use their services for a trial of 14 days. During this trial you will be given access to more than a 150TB of popular data, along with secure and anonymous access. (feature, which not always available in P2P networks)
Because of its unique structure and a separation between the client and the server, Usenet file sharing should be viewed more like DDL rather than like a traditional P2P network. That is why Bloop will soon provide support for NZB search (a "shortcut" to files on the Usenet network).