I write to recommend Vili Lehdonvirta's dissertation, Virtual Consumption, which includes several academic papers with a thought-provoking introduction and conclusion. Vili has been an important source of energy in VERN, the Turku School of Economics, the HIIT, and no doubt many other organizations that I am unfortunately overlooking.
Vili gets it all right. He directly addresses the foolish notion that virtual goods are not real, and he does so using plain-language theoretical approaches in sociology and institutional economics rather than formal mathematical models and rational choice. In so doing, he situates virtual consumption in the ongoing discussion of post-material culture.
I would especially recommend his thoughts on the idea that virtual goods are real, and that indeed there are no virtual worlds. Rather, we all participate in play worlds and different spheres of interaction, all of which share in varying amounts of "fantasy" and "reality."
Vili is not the first to say such things, of course (neither am I!!) but he makes the case extremely well and thus links the economics of consumption to broader discourses about the evolution of society in the digital age.