For me, the most interesting thing about this post is the embedded "zoom.it" graphics, which allow for amazingly smooth zooming -- without Flash or other plug-ins. Very cool.
I believe he's using Seadragon, I'm a fan of it myself. It turns our Microsoft still produces some cool stuff. It lies on top of Silverlight I believe and a similar technology underlies Bing Maps w/ Silverlight which I highly recommend trying out.
zoom.it is what was formerly known as Seadragon, but the new version does not require Silverlight.