Newsgroup are like discussion groups or bulletin boards on the internet where any topics can be discussed.
Newsgroups, collectively known as usenet are made up of computers and people that agree to exchange or pass collection of messages.Each message is called article and belongs to one or more newsgroup.People can read the articles and may reply though e-mail or post their article.Posting means distributing either an original article or response to some one else’s article and then passing in onto the network. Groups of the related message are known as thread.

How it works?

Each computer system, which is a part of usenet, runs a software to receive, manage, forward articles.The news servers administrator, using the software, maintains a list of newsgroups and a list of other usenet servers from which the computer system can receive articles.
Usenet newsgroup were circulated primarly via unix to unix file copy protocol (UUCP),later the usenet sites also became internet hosts and a network news transfer protocol (NNTP) was introduced to the internet community.NNTP is a tool for distributing articles across various news servers.

An internet user requires a client software to read the news from the news server.This software is called news reader.The news reader software lets the user browse and read through the various articles.
A typical example of a newsgroup’s name is
The seven top level newsgroup categories are given below:

Few popular news group names are;