The reason that mailman wasn't working, images weren't showing on the homepage,and I couldn't see the apache docs was.... I wasn't running apache.
Somehow, I had installed dhttpd, described as a secure web server that doesn't run cgi-bin scripts. I noticed this when I started to file a bug report, and saw dhttp listed on the dependencies. This is a little odd, since apt-cache does not show a dependency of apache on dhttpd. I also couldn't track down where debian decides which web server gets the http requests. So I'm curious to know the answer to those questions, but my immediate problem is solved.
