Security and Privacy in User Modeling

User-adaptive (or "personalized") systems take individual character­ istics of their current users into account and adapt their behavior ac­ cordingly. Several empirical studies demonstrate their benefits in areas like education and training, online help for complex software, dynamic information delivery, provision of computer access to people with dis­ abilities, and to some extent information retrieval. Recently, personal­ ized systems have also started to appear on the World Wide Web where th