This shader is very similar to the one Eric Hanson talks about in the Gnomon DVD "Digital Sets 3: Rendering & Compositing" it's used for reflecting environment maps on a cgi object.
It's designed to be blended at the compositing stage with other passes such as a diffuse pass, Ambient Occlusion, key and the other usual suspects.
Essentially it's a black blinn with the reflectivity attribute cranked up. Simple you say. But handy when you need one. I've been getting great results with blurred environmental textures. Especially as you tend to collect colour casts on the cgi object like you get in the real world. Like a reddish spill coming off a nearby brickwall, or the blue of a clear sky on top of the object.
.
Top Rated 
