I've been importing a User Group mailing list into Threads for about 6 or 7 years now... There's a pretty active group of regulars who frequent the forums not only for using the mailing list archives, but to post/answer questions as well!
It's for the BMC/Remedy User Group, which is a group of several thousand developers and administrators from about 40-50 different countries around the globe dedicated to using the
Remedy Action Request System.
Here's the link to my forums:
http://www.mattreinfeldt.com/forums/ Enjoy!
Matt Reinfeldt
Senior Support Engineer