The original 'message boards' or 'forums' of the internet. UseNet is made up of millions of 'newsgroups'. It uses the NNTP protocol.
Archived by GoogleGroups.
Linux, being a newer thing, tends to be best supported in MailingLists; however if you have MicrosoftWindows queries, you'll get better answers from UseNet (specifically MicrosoftCorporation's 'private' newsgroups) 9 times out of 10.