1 - Conical ProjectionThis is where you can paint a texture onto solids from a point like a old school projector.This would be useful for photomatching a scene, where the "back plate" geometry could be textured with a photo matching the cameras location as projected from the camera,it could also be useful for anaylitics like CCTV coverage, or special lighting effects ie that old school projector.
2 - MultiFacet/Direction ProjectionI guess UV mapping would cover this if it were supported, but as a projection method - this is where you might have several direction maps in one texture. e.g for a brick wall, you need a different texture for the top of the wall as to that used on the sides of the wall.

Regards
Robert