Usenet, short for User Network, is a distributed Internet discussion system similar to a web forum, like Neowin. You can join and participate in Usenet communities from a wide variety of places using a wide variety of readers. Usenet was started in 1979 at Duke University by graduate students Tom Truscott and Jim Ellis. In its prime Usenet has over 120,000 different active groups that users contributed to. Many of the popular social acronyms, such as LOL and emoticons, originated or were popularized on Usenet.
It seems now the Usenet era is coming to an end. On May 20, Duke announced that they will be shutting down their Usenet server due to low usage and rising costs. To add to the demise of the Usenet community Microsoft has announced the closing of their newsgroups. They are calling it the evolution of communities stating, "customers are turning online more and more for information and help. Microsoft is revamping its communities to make it easy for customers to find help and information when they need it. Using forums as the online support strategy will reduce the number of redundant resources and centralize content, making community contributions more broadly available and impactful." The newsgroups will begin shutting down in June and migrating users to the Microsoft forums.
Though Usenet was originally intended as a communication resource people found a way to share files over it as well. It became very popular among the warez community; This is one reason why so many ISPs started shutting down their Usenet servers in 2008. Since the content was not centralized sites started popping up that would help you find what you were looking for. They would offer NZB files, similar to torrents, that would point you in the direction of the content you were looking for. For awhile these sites seemed to stay off the radar of the movie and recording industry. It seems the studios have caught up with the Usenet community now, Newzbin, a popular NZB site, has been shut down after a legal battle with the with the MPA. Much like The Pirate Bay, Newzbin never actually hosted any illegal content only files pointing to the content.