Context-aware computing offers the promise of significant user gains-the ability for systems to adapt more readily to user needs, models, and goals. Dey, Abowd, and Salber (2001) present a masterful step toward understanding context-aware applications. We examine Dey et al. in the light of privacy issues-that is, individuals' control over their personal data-to highlight some of the thorny issues in context-aware computing that will be upon us soon. We argue that privacy in context-aware computing, especially those with perceptually aware environments, will be quite complex. Indeed, privacy forms a co-design space between the social, the technical, and the regulatory. We recognize that Dey et al. is a necessary first step in examining important software engineering concerns, but future research will need to consider how regulatory and technical solutions might be co-designed to form a public good.