What is nearfield listening?

I had someone "in the industry" who some of you have bought products from tell me that nearfield listening doesn't have to do with actual distance from the speakers, that it refers to whether you are sitting inside or outside a 60 degree angle from the speakers.

Secondly, what are the drawbacks to sitting close to your speakers? I figure that there are advantages like being able to pull your speakers far out from back and side walls and also that the listening seat can also be far from the back wall.