While some mailing lists are not controlled in any way, others are supervised in that each message sent to the list is reviewed by a moderator who then decides whether to allow the message to be sent on to members. Similarly, the acceptance of new members to a list may be controlled by a moderator. News groups newsgroups, which operate on the Usenet system, perform a similar function to mailing lists with the important distinction that they are accessible by all users. The Usenet newsgroup systems are an informal worldwide grouping of people and their computers. A newsgroup functions like an international meeting place where people can gather, talk informally with others and discuss matters of common interest.
Any user can access and read newsgroup articles and can also post articles.
The possible exception to this is where there is an individual who monitors and exercises some control over the 'conversation' taking place. However, relatively few newsgroups are moderated in this way. The Usenet newsgroups provide an environment in which a wide range of topics is discussed. These include such things as hobbies, areas of common interest, politics, religion and sex. Bulletin boards are the forerunners of newsgroups and typically operate as stand-alone systems.