Web interface: makes it easy for people to subscribe, leave and change their settings. Can also search, read and contribute from the web.
Fast text searching: all archives are indexed for fast searching.
Confirmation: new subscriptions can send a "are you sure you want to join" message to confirm their email address, and to ensure someone else did not subscribe that person as a prank.
Compatible: accepts most list server commands.
Protected membership: mailing lists can be set up so that new members must be a) approved by an administrator b) must know the new member password c) can join without approval d) cannot
join, the administrator must add them.
Visitors: mailing lists can allow visitors to read and search the archives on the web, but they cannot contribute to the group.
Multi-lingual: supports mailing lists in a number of languages
Easy upgrade from other programs: imports your current member list and mailing list archives for an easy transition.
Spam protection: number moderating feature virtually eliminates spam. By requiring new members to have their first message approved, you can keep spammers from joining your list just to spam
Moderating: supports several moderating models. All members can be moderated, selected members can be moderated, selected members can be unmoderated (but everyone else is).
Number moderating: an option for new members to have their first few messages approved, thereafter they can contribute unmoderated.
Web based moderating: you can approve or reject batches of messages at a time using the web interface.
Date moderating: can have moderated messages be automatically approved after a given time period.