For a project I am doing for one of my customers, I needed a mailing list archive. I looked, and it seems the nicer one is Lurker.
Sadly, there are no RPM packages, so I had to build it manually... and ran into mimelib. Which, looking closer, is the same mimelib from Doug Sauder I used in KRN back in the late 90s.
And which I had a hand in GPLing, too. And it's still in use. One of the things I always liked about FLOSS: nothing ever really gets thrown away.