I saw this question and learned it's very tricky to export material from Cycles for other applications' use. So let me clarify: I only work with Blender.
Previously while I was working with BI, I can export a plane as a
.obj file specifying the geometry and an accompanying
.mtl specifying the material, such as specular and diffuse colors, etc. If I import this
.obj file back to BI, I get every setting back.
Now I switch to Cycles. I create a glossy material for my cube and export it as usual. Now if I re-import this
.obj file back to Cycles, my material settings are all gone.
What is the proper way of exporting a Cycles material?
P.S.: It would be wonderful if the answer could be given from the Python API perspective. :-)