Focus: Security and Privacy on the Web

WITH THE ADVENT of targeted advertising and the popularity of data mining, users find their privacy threatened. To address this rising concern, researchers have proposed many privacypreserving mechanisms.1 Most of these mechanisms have strong theoretical guarantees but often lack practicality. For instance, reaching a sufficient level of privacy often requires sanitizing (distorting) user data to the point where it is no longer usable. PriView is an interactive system for video consumption that provides privacy transparency and control while maintaining the quality of video recommendations based on user ratings. It shows how informationtheoretic privacy can lead to practical policies for protecting user profiles while maintaining the sanitized data’s utility.