Usenet is a collection of user-submitted notes or messages on various subjects that are posted to servers on a worldwide network. Each subject collection of posted notes is known as a newsgroups. There are thousands of newsgroups and it is possible for you to form a new one. Most groups are hosted on Internet-connected servers, but they can also be hosted from servers that are not part of the Internet. The original protocol was UNIX-to-UNIX Copy (UUCP), but today the Network News Transfer Protocol (NNTP) is used.

Usenet is mostly accessed via newsgroup readers, such as Outlook Express, that run as separate programs.