Crowdsourcing as a model for distributed problem solving has been rapidly gaining in popularity. In investigating what drives the solvers to participate in crowdsourcing, the extant research has one-dimensionally only viewed the origins of motivation. While these studies have revealed that crowdsourcing systems’ use is driven by both intrinsic and extrinsic motivations, they fall short of explaining how these motivations change over time from initial to continued use. To address this research gap, our study highlights the dynamic nature of human motivation and shows that by including the aims of motivation in the analysis, we can better capture the dynamic nature of motivation across time. With a case study of a photography crowdsourcing platform, we illustrate how the solvers’ motivations change from the initial use to sustained participation. While initial use seems to be inspired by selfish motivations, continued use requires both selfish and social motivations to be satisfied. This study contributes to theory by extending our understanding of the motivational factors driving the use of crowdsourcing systems by looking into both the origins and the aims of motivation together with the temporal dimension. It also contributes to practice by providing suggestions in terms of communication strategies for crowdsourcing organizers.