Knowledge sharing is particularly important for co-creating, discussing, or acquiring innovative ideas. Crowdsourcing, as an enabler of open innovation, has raised the question about the kind of organising forms and/or managerial interventions it may require or underpin. However, there is little consensus in management studies on how to best design a crowdsourcing initiative (contest) with regard to the mechanisms to engage an online community. In this paper, starting from an exploratory case study on the project “Stati Generali della Formazione e del Lavoro” (General Assembly on Training and Work)—a crowdsourcing experience designed for a large community of professional trainers, planned and managed by University of Milano-Bicocca and AIF Academy (Associazione Italiana Formatori), a broad representative association of Italian trainers—we study the factors influencing the decision of the participants (a.k.a., solvers) to become involved (and to what extent) in a contest. The study could contribute to the debate on crowdsourcing by both underlining important governance factors involved and providing empirical evidence of the link between management strategies and crowdsourcing success.