This is not directly Linux related, but in our current incarnation we run mailman on an Ubuntu server on Amazon in I believe an EC2 instance
It is a pretty active mailing list. Far more active than this one for the local beer and brewing community.. Currently costing about $37 a month and we are looking for a way to reduce that. Maybe with fully hosted service where we do not have back end control or something like that. Just a GUI to manage. Not finding much in Google in terms of options. Most things that come up appear to be geared towards blasting out emails in marketing campaigns. -- "You should sit in nature for 20 minutes a day. Unless you are busy, then you should sit for an hour" - Zen Proverb