When crowdsourcing intermediaries lose crowd members, they lose potential high-quality solutions in the future. As the number of contests and intermediaries grows, it is increasingly critical for crowdsourcers to meet the needs of solvers and avoid seeing them migrate to the competition. Besides winning contests, intensive communication and customized feedback are solvers’ most central needs. For this study, we surveyed 202 solvers about the importance of communication in crowdsourcing contests. Based on our quantitative and qualitative insights, we derive key principles that can help crowdsourcers maintain and grow their solver base.