Ever heard of Usenet? It is a system that has been around since 1980, although has not received much attention since the dawn of the broadband era. That being said, Usenet is still alive and well and has a few tricks up its sleeve.

So what is Usenet? Let’s start at the beginning. Usenet is a worldwide distributed Internet discussion system. Users read and post messages to one or more categories, known as newsgroups. These newsgroups are organised into hierarchies of subjects, for example “comp.”, which covers computer-related discussions (e.g. comp.software and comp.sys.mac). The system can be thought of as the predecessor to modern day Internet forums.

So what makes Usenet special? Usenet has no central authority. Instead you have a number of newsgroup servers distributed across the globe, normally hosted by organisations and institutions, Internet service providers and dedicated Usenet service providers. When an end user posts to a news server, the message is stored locally on that server. That news server then forwards the message to all of its network neighbours that haven’t yet seen the article. The message then continues to propagate across other news servers, however only one copy of a message is stored per server. The image below helps explain the process:


As you can see from the diagram, a collection of Usenet servers has a peer-to-peer (P2P) feel to it, in that each server shares resources by exchanging them. However the big difference is that the end users don’t share the resources like they would with other traditional P2P systems, such as BitTorrent.

So why use Usenet? We mentioned that the Usenet messaging system is like a predecessor to Internet forums. This in itself is not that exciting, however Usenet also has the ability for users to share files (of any size). When you search the news server you are connected to for a particular file, it will check to see if any matching content has been propagated (and chances are it has). This means that you are able to download this content directly from your news server (even over SSL), while not having to re-share (upload) the content like on a traditional P2P network.

This gives you a basic overview of Usenet, which should be enough to get you started. As with all things, the best way to learn is to get stuck in and therefore my suggestion is to head over to Panic’s website (the guys behind the awesome Transmit and Coda) to download the free trial of Unison, which is their award winning Usenet client for the Mac. Panic even offer a free 24 hour pass to their news server to help get you started.

In the following weeks, I will post a follow-up detailing how to get started with Unison and take advantage of it’s advanced (but simple) feature set. Until then, have a play and don’t worry you can’t break anything.