An on-line discussion group, originally at USENET.

On the Internet, there are literally thousands of newsgroups covering every conceivable interest. Newsgroups are distibuted via special protocol NNTP (Network News Transport Protocol). To view and post messages to a newsgroup, you need a news reader, a program that runs on your computer and connects you to a news server on the Internet. Some newsgroups have parallel mailing lists for Internet people with no newsgroups access, with postings to the group automatically propagated to the list and vice versa.

Newsgroups can be "unmoderated" (anyone can post) or "moderated" (submissions are automatically directed to a moderator, who edits or filters and then posts the results). Some moderated groups (especially those which are actually gatewayed Internet mailing lists) are distributed as "digests", with groups of postings periodically collected into a single large posting with an index.