Yeah, like about only 60000 hits.
Looks like using the view normal to lookup into a spherical texture.
Yeah, I'm pretty sure it's ultimately identical to any other kind of environment mapping (cube mapping, sphere mapping, etc.) in that it's ultimately just a function that maps angle to color. The only advantage I see is that it represents the function in a fairly intuitive way (and it's easy to capture from paintings, photographs, etc. of a spherical object) and that it stores the most resolution for angles that point toward the camera. The disadvantage is that it's actually only half of an environment map.