Privacy is a critical challenge for the mobile application ecosystem. US policy approaches to mobile data protection rely on privacy by design: approaches that encourage developers to proactively implement privacy features to protect sensitive data. But we know little about how application developers define privacy, how they decide to implement privacy features, and what might motivate them to consider privacy as a primary design value. This project identifies these factors by investigating the discussion of privacy as a professional practice within a community of mobile application developers. Analyzing posts on an iOS forum reveals that privacy is a frequent topic of conversation in this community. This paper describes how iOS developers define and legitimate privacy, and reveals a challenge: iOS developers rely heavily on a definition of privacy provided by Apple which does not reflect current empirical or theoretical understandings of how users understand privacy. Understanding this challenge can help us shape better guidelines for privacy by design, and broach challenges to the widespread adoption of privacy by design principles
