wait a sec.  allowing commercial use is not the same as allowing distribution.  commercial use is  making images with something and selling it.  not distributing it as a part of your own material pack.

that would be a merchant resource, and really, i don't know the stance on that. 

in my opinion, materials are a very grey area.  i'm very comfortable in the material room, and i think i'm OK at making my own materials.  but what i'm doing is applying knowledge i've learned from others who have posted to the forums.  unlike advice on texturing, this means actually posting node combinations.  accurate solutions in the material room are specific.  i'm not sure if one can distribute anything with parts of other people's materials without their permission, but who can say their material is completely without basis on anyone else's work?