Where.gov - Good Idea or Utopian Ideal?

Christopher Tucker put forth this clear and simple vision in Federal Computer Week yesterday:

From the lowliest citizen to the president of the United States, we should all be empowered to fire up an application I will call Where.gov. At that portal, you could draw a bounding box on a map, declare a slice of time and instantaneously discover everything our government knows about that place. And we should be able to marshal that data instantaneously to support our needs.

To me this encapsulates all the recent talk of Gov2.0, open standards, cloud computing, common platforms, and GIS one stop-shopping.  This vision is simple and idealistic. We welcome you comments on whether this should or should not be a proper vision, what obstacles are in its way, or what factors you think make it impossible.