We conceptualize mechanisms that explain how social uses of media technologies, especially online platforms and crowds, reproduce, or modify inequalities, and explore these in the context of the
crowdfunding of science. We distinguish between \"supply side\" factors related to the ability of actors given their institutional standing to use this funding approach, and \"demand side\" factors related to the crowd\'s sensitivity to the institutional standing of those actors. We collected data on scientists requesting funding for their studies on Experiment.com , arguably the most popular scientific
crowdfunding platform, and investigated the factors contributing to initiation and success. Supply side factors were important:
crowdfunding appeals tended to come from scientists affiliated with larger, wealthier, and more active and prestigious institutions. However, demand side factors were not as important at the institutional level.
Crowdfunding projects\' success was not predicted by the institution\'s status, but rather by the number of appeals from an institution.