This web site? Strangely, it's written using a e-commerce and "CMS" (I use the term loosely here) that I wrote with another company.
Basically, it's proprietary and has some very cool features I built that DNN wouldn't have such as a global event bus for programming and a Inversion of control event bridge.
How cool is that? It republishes IoC events from the YAF.NET bus onto my CMS bus so I can respond to them from either.
Anyway, it's not nearly as easy as DNN -- but I like it a lot more. Gives me full control over all systems.