This work highlights the importance of informal control modes on software platforms regarding their positive effects on third-party developers' behaviors and outcomes. The author presents studies in the mobile software industry, demonstrating how self-control and clan control positively affect developers' outcome performance, app quality and intentions to stay on software platforms. Moreover, the studies' findings shed light on the underlying explanatory mechanisms of why informal control modes can be exercised effectively on software platforms and how especially clan control may be facilitated through developers' social capital.