Mailman is software to help manage email discussion lists. Mailman gives each mailing list a web page, and allows users to subscribe, unsubscribe, etc. over the web. Even the list manager can administer his or her list entirely from the web. Mailman also integrates most things people want to do with mailing lists, including archiving, mail-to-news gateways, and so on. Please check the Mailman Website for more information.