On the Icehouse list, Craig asked me to chime in on experience with forum software and its capability to host all the lists while also maintaining listserv functionality. OK.
I use Simple Machine Forum on
http://glasscutter.org/forums and it allows for notification of new topics and of replies to topics in which you reply. So you can:
* get a notification for each new topic, on any and all board(s) (i.e. sub-forums) you choose, and
* automatically or electively be notified of replies to topics in which you post.
It does not, however, work in reverse: you can't email the forum and make a new topic or reply. And there is no Digest functionality to speak of, aside from the obvious "digest view" of looking at a boards list of topics (new ones are bold).
I don't suppose it's really worth the hassle of a transition, anyhow. Mail is fine, even though a LOT of folks don't know not to top-post... and I am in the habit of deleting almost all list mails anyway, because I can always go to the archives. I guess it's just that I like the "sandbox" that is a forums--it's not "in my face" until go to the forum--and I REALLY like the option to format text or embed images or what-not (within reason). If Mailman had a way to automatically cull obvious top-posting and allowed HTML mail, I'd not care a whit.
Anyhow... I was asked, and I answer.
HTH;
David