I was investigating the Mojo Mail site application and came across this
http://mojo.skazat.com/ and this http://mojo.skazat.com/project/glad.html.
I've decided to use Dada Mail instead of the WestHost Mojo Mail and I thought I'd pass the word along.
Or just use Mailman (http://list.org) which is WAY cooler than Dada Mail (but is a pretty involved SSH install, and requires a lot more maintenance because of our VPS structure).