Usenet

Usenet (Unix User Network) is a service on the internet, which offers discussion forums (newsgroups) of all kind. The functionality of Usenet can be compared with a public pin board. A user writes a message and sticks it on the pin board, where everybody can read it. If someone wants to reply on a certain posting, he or she can write a message as well and stick it underneath the original message.

Basically Usenet works identically and controversial issues can quickly end in huge threads.
The first Usenet-connection was established in 1979 by Tom Truscott, Steve Bellovin and Jim Ellis between two UNIX computers at Duke University and the University of North Carolina.
Usually NNTP is used to read back or forward a Usenet posting.