Daniel Ehls analyzes the impact of contextual factors on attracting volunteers into open initiatives. He answers challenging questions like why do users join one community over another and what are attractive conditions for user and open innovation With a discrete choice experiment, Daniel Ehls identifies openness trade-offs and joining preferences contingent on access, usage and sponsorship. Also, he reveals causes of taste heterogeneity and shows how context and personality determine joining decisions. Management insights target organizational behavior, e.g. how the governance structure affects user actions, and competitive strategy, e.g. how to source external distributed knowledge.