Electronic mailing list
Electronic mailing lists are a special usage of email that allows for widespread distribution of information to many Internet users. Software is installed on a computer which processes incoming email messages, and, depending on their content, either acts on them internally or distributes the message to all users subscribed to the mailing list. Popular examples of mailing list software include GNU Mailman, Listserv and Majordomo. Today, mailing lists are most often used for collaboration on various projects and as a way of distributing current news and other such information. One very popular mailing list is Bugtraq.
Sometimes these take the form of what is termed a "discussion list": a subscriber uses the mailing list to send messages to all the other subscribers, who may answer in similar fashion. Thus actual discussion and information exchanges can happen. Mailing lists of this type are usually topic-oriented (for example, politics, scientific discussion, joke contests), even if the topic can range from extremely narrow to "whatever you think could interest us". In this they are similar to Usenet newsgroups, and share the same aversion to off-topic messages. The term discussion group encompasses both these types of lists and newsgroups.
Free web-based services offering an easy way to run and maintain such lists were popular in the late 1990s, but many of these were taken over or went bust, so that the only popular provider is now Yahoo! Groups. This is used by a wide range of groups, including organisations who might at first glance be considered 'rivals' to Yahoo! MSN Groups appears to be pushing hard to catch up to Yahoo!. Freelists.org is a web-based service using all-free software, though it may be more difficult for some users to set up.
Some mailing lists are open to anyone who want to join them, while others require an approval from the list owner before one can join. In even more strict mailing list, every message must be approved by a moderator before being sent to the rest of the subscribers. Moderator approval is usually employed to keep a high average quality of posts and weed out spam. While sometimes people see those restrictions as contrary to freedom of speech, this position is quite unrealistic: a different mailing list with more open rules can be started by anyone.
- Free mailing list software: