This study investigates whether and how a platform's provision of performance feedback to users about their prior content contributions can help to stimulate users' subsequent contributions. We draw on social value orientation theory to hypothesize how different framings may impact users' likelihood of producing additional content. We partnered with a major mobile crowdsourcing platform based in China to conduct a randomized field experiment involving the delivery of feedback messages with randomly determined framings, via mobile push notifications. We find that feedback framed either pro-socially or pro-self has a positive effect on content contributions, whereas feedback framed competitively has no such effect. Additionally, we observe differences across genders, such that the positive effects of pro-socially framed feedback are significantly stronger for female users. In contrast, competitively framed feedback is only effective for male users. Our findings provide implications for the design of platform-provided performance feedback to stimulate users' content contribution.