Hmm... sorta. You can get some pretty interesting effects by connecting nodes in new ways. Now it sounds like you're confusing nodes and attributes a bit. Intensity is an attribute of a light's shape node, so it's integral to lights, however, you could connect nodes via Intensity and get some interesting intensities or such. It really depends on the nodes and attributes, but theoretically I think you could plug some fog into a certain light attribute and get something.

Bottom line is yes, by all means use nodes beyond what they were intended to do originally. I'm working through the Special Effects Handbook by Eric Keller and he does that a fair bit, using an ambient occlusion node to generate different effects etc.