Who, when, where: Obfuscation preferences in location-sharing applications (CMU-CyLab-11-013)

This paper presents a study of obfuscation practices in location-sharing systems. The study shows that users have relatively complex preferences that depend on the recipient of the location, the time of the request and location. The preferences also require multiple levels of obfuscation (ranging from disclosing no location information to disclosing the exact location) to accurately capture. For example, we find that users tend to reveal finer-grained locations to recipients with closer ties, such as family members, but coarser-grained locations to colleagues and strangers. We also find that users utilize the full range of obfuscation options, from high-level region to exact address, which further demonstrates the complexity of their preferences and highlights the importance of obfuscation as a privacy control. Additionally, we find that day of week and type of location affect users' decisions on how much detail to share.