This site uses the Dokuwiki engine. I primarily chose Dokuwiki because it features strong access control, which is essential to designing a wiki that looks like a regular website to the normal viewer. I also selected Dokuwiki because it's free and open source, has an active user forum, stores its data in files rather than a database, and is easily extended through its plugin architecture.
The look and feel of the site is based on Civilized, a free CSS template available at Free CSS.com.
StableHost handles the hosting duties for the site. They're paradoxically crazy reliable and cheap as can be. The best review I can give them is to tell you to Google “stablehost sucks.” Go ahead, give it a whirl.