Designing a Social Protocol: Lessons Learned from the Platform for Privacy Preferences

The Platform for Privacy Preferences Project (P3P), under development by the World Wide Web Consortium (W3C), enables users and Web sites to reach explicit agreements regarding sites' data privacy practices. The options chosen in developing the protocols, grammar, and vocabulary needed for an agreement lead the authors to a number of generalizations regarding the development of technology designed for "social" purposes. In this paper we will explain the goals of P3P; discuss the importance of simplicity, layering, and defaults in the development of social protocols; and examine the sometimes-difficult relationship between technical and policy decisions in this domain.