Moving towards life-long User Modeling

User Modeling is the core component for the majority of personalization services. It has become an important factor in the effort to personalise a diversity of web resources according to users' characteristics and needs. While trying to move a step further and model dynamic users in a range of contexts, life-long User Modeling, the ability to model a dynamic and changing user throughout lifetime interactions with a variety of resource providers, appears to be an attractive solution. A Scrutable User Modeling Infrastructure is proposed in this paper, where a first prototype has already been designed and implemented, which blends together some key User Modeling 'ingredients'- interoperability, scrutability, user privacy - and attempts to model the various life-long user interactions with a diversity of web-based systems from the educational, business and social networking domains.