Mailman is the GNU mailing list manager. It provides standard list management features, integrated with a web interface. Please note: the subversion repository has been retired. Please see http://wiki.list.org/x/DgAJ for details.
ISOS is an e-mail and web server. It is designed for ease of use and provides a quick way to e-presence for small businesses and organizations who lack the experience to benefit from high performance, open source software such as Sendmail, Courier Mail,