"The rest should just be called AUX1, AUX2, AUX3, etc." Then everyone would be asking "what are these inputs for?". The names are for convenience: Alternate_Diffuse is a place where you can plug the diffuse nodes into, Alternate_Specular is where you can plug the specular nodes into. You don't [b]have[/b] to - but following this convention will make it easier for other people to understand your shaders.