This is called "Carmack's Reverse", and was used for the realtime stencil buffer shadows in Doom 3: http://en.wikipedia.org/wiki/Shadow_volume

Stencil buffer shadows were very popular in the mid 2000s because of their performance and relative simplicity in implementation. Their main drawback is that there is no easy way to get a soft penumbra around shadow edges. You can spot them in many games from the last generation because of their universal hard edges -- an area is either in shadow or not. See: Mario Galaxy, etc.