Abstract
For the Fab City Initiative to be a success story, many citizens must internalize its vision. Thus, a key success factor is the widespread adoption of user-generated Fab Lab products. However, user innovators have currently little incentive to bear the cost of active diffusion efforts which leads to welfare losses. To overcome this so-called diffusion shortfall, we present promising voluntary payment mechanisms that could act as a decisive incentive for user innovators without losing the idea of an open community and give respective research directions. Moreover, we discuss potential adoption barriers of end users (e.g., safety or quality concerns) and suggest how a trusted Fab City seal might be helpful in overcoming them.