Any recommendations for some forum software that fully supports listserv-style email discussion list functionality? Specifically, a forum that users can access online in the typical fashion or choose to interact with it strictly through email (both sending and receiving messages) like a traditional email discussion list (like mailman or majordomo). Let me emphasize that a forum with simple outbound notification is not sufficient -- I need email responses from users to post back to the forum.
I'd accept a reasonably priced hosted solution as well if it has good support. Yahoo and Google groups feature email access, but I need more support than either of those free hosting providers offer (if something breaks I need to be able email or actually talk to someone to get it fixed).
+2 points for actively maintained open source software +1 point for user account integration with some CMS +1 point for NNTP support at the same time (probably a pipe dream :) +X points for nice feature set (email bounce handling, moderation, good SEO, etc.) +1 point for Windows hosting compatibility
So far the only option I've really found is the enterprise edition of ActiveForums for DotNetNuke. Surely there must be other packages like this out there though. Any suggestions?