How open is open innovation? User roles and barriers to implementation. In Rico Defila, Antonietta Di Giulio, and Ruth Kaufmann-Hayoz (Eds.), The Nature of Sustainable Consumption and How to Achieve it. Results from the Focal Topic „From Knowledge to Action – New Paths towards Sustainable Consumption”, 309-322, Oekom, München, 2012. [PUMA: innovation Sowi5CK barriers implementation roles user open]