One of the most popular Usenet indexing services on the internet, NZBMatrix, has shut itself down voluntarily over piracy troubles. According to the site's owners, who published a farewell notice on the site, a huge DMCA takedown request was posted to the site on behalf of a number of entertainment companies including Sony Pictures and Warner Bros. - a request so complex that policing the site's indexing bots would become "an impossible task."
This issue with piracy was also compounded by problems with payment systems, which the owners claim were unstable and constantly pulling out. The costs for the site in the end were huge, and thanks to uncooperative payment providers as well as huge DMCA takedown notices, the site became too hard to manage.
The site ends the statement by indicating that by constantly removing pirated content from its indexes, the indexer becomes irrelevant:
Also the Usenet Indexing scene is going through some changes, with content being removed from pretty much every provider its making the existence of an indexer irrelevant if the content does not even exists anymore.
NZBMatrix was extremely popular in the Usenet community as an easy way to find content, most often pirated, and this shutdown (along with Newzbin2 last month) continues the vicious war by copyright holders to make it harder for people to obtain content for free.