Description:

Mailman, the GNU Mailing List Management System, is a mailing list
management system written mostly in Python. Features:
- Web based list administration for nearly all tasks. Web based
subscriptions and user configuration management. A customizable
"home page" for each mailing list.
- Privacy features such as moderation, open and closed list
subscription policies, private membership rosters, and
sender-based filters.
- Automatic web based archiving built-in with support for private
and public archives, and hooks for external archivers.
- Per-user configuration optional digest delivery for either
MIME-compliant or RFC 1153 style "plain text" digests.
- Integrated mail/Usenet gateways.
- Integrated auto-replies.
- Majordomo-style email based commands.
- Integrated bounce detection within an extensible framework.
- Integrated spam detection, and MIME-based content filtering.
- An extensible mail delivery pipeline.
- Support for virtual domains.

See the Mailman home site for current status, including new releases
and known problems: http://www.list.org/