Lifting from my 2009 thread:

A decent run-down on various specular reflection models is here.

http://en.wikipedia.org/wiki/Specular_highlight

There is a confusing nomenclature in Poser regarding "Phong". There is a Phong node, but it does not implement what is now called the Phong Reflection Model. It implements something that Mr. Phong used in the 70's which has now been discarded because computers are so much faster - we can use better models.

With some subtle differences and variation, we can make these connections:

The "Phong distribution" explained in that wikipedia article is what in Poser is called the Specular node.

The "Ward anisotropic distribution" is our Anisotropic node.

The "Cook-Torrance model" is our Blinn node. (As far as I can tell, Blinn took the Cook-Torrance model and improved upon it - resulting in the Blinn-Phong reflection model. Or something like that.)

The Glossy node is none of these. It is a clever little cheat to deal with the fact that our CG lights are effectively point sources. A point light has no dimension, and a perfect glossy specular reflection of it would have no dimension, either. The Glossy node ignores that little fact. It simulates what you'd get from a glossy surface if the light actually had some finite width to it.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)