We are one of the most extensive archives of Usenet newsgroups on the Internet, currently archiving 317 million posts in 10 thousand unique Usenet newsgroups. The free of charge access is possible via the web interface, without a requirement for a third party Newsreader.
To access a specific newsgroup, select a topic of your interest through the 'Categories' menu and then navigate to the discussion threads and posts.
While archiving millions of Usenet discussion, currently, only the newsgroups with at least 100 posts and the discussion threads with 1 or more replies, are publicly accessible.
A private, non-federated NNTP server that hosts newsgroups. Apply for an account, configure a news client, enjoy.
Eternal September is a free online Usenet feed for people who still feel the need to read net.news. You can only access text newsgroups (i.e. no alt.binary.*) and you have to register an account, but other than that it's open season. They also support UUCP if you roll that way.
Free datasets made available by Amazon. Stuff like an atlas of the Galactic Plane, NASA NEX data, the Human Microbiome Project, the Enron emails, Freebase, and the Marvel Universe's socialgraph. The Google Books Ngrams corpus is in here, also, alongside the Westbury Lab USENET corpus.