Message posted at:You might know these as newsgroups. usenet was one of the earliest systems available on the internet - it is, more or less, an incredibly large bulletin board with many thousands of topics and many, many posts within each topic. It was decentralised, so an organisation could choose to run its own server, and then subscribe to all or just topics of its own choosing, and in turn, share its own posts with other usenet servers.
Optus News Server removal
Optus has previously provided usenet service (Optus Newsgroup) to customers. However, following evaluation of the services that we offer to our customers, and the declining usage of usenet by our customers over the past several years, it is no longer viable to continue to provide this service. As a result, the usenet service is in the process of being disabled and removed. This service will close as of 21/11/2011. If you still want to use usenet, there are a number of commercial usenet providers that will be able to provide this service to you.
There is a sense of hierachy, so comp.networking.tokenring was part of networking, which was part of computers. There are roughly nine major top levels, such as comp, news, rec and alt. Many years ago I used to frequent rec.sport.mountainbiking and aus.legal for example.
The system was clever, in that a server didn't need to be online all the time. It could dial up another server or ISP, exchange posts, then disconnect again, much the way email used to be transmitted using UUCP.
As you can see, Optus is decommissioning its usenet servers, but various sources how that the amount of data posted per day continues to rise. However, I suspect that much of that data is unlawful sharing of binary data, such as movies, software, TV and music.
Usenet also helped give birth to actions for defamation on the internet. The most famous cases revolve around Dr Laurence Godfrey, who sued a number of internet service providers and universities who hosted usenet servers. In each case he requested that a defamatory posting be removed from the usenet server. Of course, since usenet posts are propagated across the world very quickly it is almost impossible to control them. If a usenet server is subscribed to a particular newsgroup it will simply receive all the posts.
His first action against Demon Internet Limited (Godfrey v Demon Internet Limited  4 All ER 342) was relatively novel, dealing with the "secondary publisher defence" under the UK Defamation Act 1996. Demon failed to take down a posting after being notified of its existence, and the UK High Court upheld Godfrey's argument that it ceased to be a protected secondary publisher once it was on actual notice. An excellent analysis of the British law at the time and proposed reforms can be found here. The case has been followed many times since, and formed the foundation of changes to laws all over the world.
Various organisations have attempted to archive usenet postings, including Google Groups, where I can find things I wrote in usenet from 1994 onwards, such as those celebrating the birth of my daughter, and issues using HyperCard 2.2 with Oracle 7.
So, while not being a huge user of usenet any more, I'll be sad to see its demise.