After looking for informations about postfixadmin and mailman I get from irc/cboltz the link to the wiki page. This page was not linked from main page so users couldn´t find the good informations.
FYI: It's linked indirectly via the "Example Configs" category.
I'm not sure if having every single page linked from the main page makes sence - maybe it does currently because we don't have too many pages, but with more pages (am I dreaming? ;-) the result will be a very big main page...
That said: the wiki is in a very early state and probably needs improvements at various places. If you want, I can give you write access - just drop me a note.
With the move to the new wiki, I added links to all pages on the main page.