Use it, Love it
We're using version 1 of this software and it works great. The interface is simplistic looking but works, and we've rarely had a problem with sending mailings.
This article appeared on linuxtoday too.
Someone there mentioned you can already get a stripped down web server for Win9x, the Personal Webserver with Frontpage.
Issues of stability would deter most from using Win9x as a web platform anyway. Not at first of course, but once their machines have crashed for the umpteenth time..