This study identifies and explores evolving concepts of trust and privacy in the context of user-generated health data. We define “user-generated health data” as data captured through devices or software and used outside of traditional clinical settings for tracking personal health data. The investigators conducted qualitative research through semistructured interviews with researchers, health technology start-up companies, and members of the general public to inquire why and how they interact with and understand the value of user-generated health data. We found significant (...) results concerning new attitudes toward trust, privacy, and sharing of health data outside of clinical settings that conflict with regulations governing health data within clinical settings. Members of the general public expressed little concern about sharing health data with the companies that sold the devices or apps they used, and indicated that they rarely read the “terms and conditions” detailing how their data may be exploited by the company or third-party affiliates before consenting to them. In contrast, interviews with researchers revealed significant resistance among potential research participants to sharing their user-generated health data for purposes of scientific study. The widespread rhetoric of personalization and social sharing in “user-generated culture” appears to facilitate an understanding of user-generated health data that deemphasizes the risk of exploitation in favor of loosely defined benefits to individual and social well-being. We recommend clarification and greater transparency of regulations governing data sharing related to health. (shrink)