This study investigates how user innovation can be used as an engagement mechanism for crowdsourcing-based marketing initiatives. By building on an in-depth case study of a hamburger chain’s crowdsourcing initiative, we analyze key activities in customers’ value-creating processes, the crowdsourcer’s value-creating processes, and innovation encounter processes. We further identify three key activities by which a crowdsourcer can facilitate the realization of desired outcomes from the crowdsourcing initiative: (1) the development of opportunities for user innovation, (2) the planning of user innovation activities, and (3) the implementation and assessment of the outcomes. Our results emphasize the importance of activities and technical features that enable socializing with other participants, support active participation, and create a participatory experience. Our study will inform research and practice on crowdsourcing and user innovation for marketing purposes.