The language of privacy
ACM Transactions on Computer-Human Interaction
This thesis informs the design and development of video media spaces that enrich distributed collaboration and preserve privacy. Video media spaces are fully interconnected multi-person audio/video networks that are usually on all of the time. They have the potential to benefit distributed teamwork by providing rich informal awareness and casual interactions to distanceseparated colleagues. However, the problem is that media spaces may be invasive to privacy. Although there are techniques
... ed to preserve privacy in video media spaces, e.g., video blurring, their effectiveness and usability are not known. Furthermore, there is insufficient theoretical knowledge about what privacy is and how it should be supported to guide the design of privacy-preserving video media spaces. In this thesis I describe four major contributions that fundamentally change our understanding of the nature of privacy, its role in people's daily lives, and how it may be realised in computer supported cooperative work (CSCW) systems. First, I developed the COLLABRARY toolkit to rapidly prototype video media spaces and privacy safeguards so that I could understand the human factors of their design, implementation, and use. Second, I evaluated the blur and pixelize distortion filtration techniques. These studies suggest that although they are widely suspected to be useful for mitigating privacy issues in video media spaces, these techniques fail to adequately balance awareness and privacy in high-risk scenarios. Third, I developed a comprehensive descriptive theory of privacy in video media spaces based on the social, psychological and CSCW literature about privacy. It decomposes privacy into three normative controls for regulating interpersonal boundaries in an embodied dialectic: solitude, confidentiality and autonomy. This theory yields a powerful vocabulary of terms that disambiguate the many interrelated and subtle meanings of "privacy." iv Lastly, I developed a systematic method for applying the vocabulary of the descriptive theory of privacy to analyse and describe video media space design and use. This method reveals omissions in the way a media space prototype handles privacy and hidden assumptions regarding technology design, use, users, and their contexts. I illustrate this method in several case studies that generate further analytical knowledge about privacy in video media spaces.