Privacy concerns and protection measures in online behavioural advertising

Online Behavioural Advertising (OBA), the practice of showing advertisements based on a person’s web browsing behaviour, has become a vital component of the ad-supported web. The tracking of users’ browsing behaviour that is needed for OBA, however, raises privacy concerns. We give an overview of the OBA landscape, and describe which user information is collected, which techniques are used to perform the collection, and how user information is shared between companies. Moreover, we discuss the privacy concerns that are raised by current OBA practices. After identifying privacy concerns, we describe a range of existing techniques to protect user privacy in online advertising. These techniques are compared based on their feasibility in the current advertising ecosystem, including the potential utility they offer advertising companies and how well they can be integrated with current trends in online behavioural advertising. Finally, we identify open problems in the protection of user privacy in online advertising.