  Personalized adaptation technology has been adopted in a wide range of
digital applications such as health, training and education, e-commerce and
entertainment. Personalization systems typically build a user model, aiming to
characterize the user at hand, and then use this model to personalize the
interaction. Personalization and user modeling, however, are often
intrinsically at odds with each other (a fact some times referred to as the
personalization paradox). In this paper, we take a closer look at this
personalization paradox, and identify two ways in which it might manifest:
feedback loops and moving targets. To illustrate these issues, we report
results in the domain of personalized exergames (videogames for physical
exercise), and describe our early steps to address some of the issues arisen by
the personalization paradox.
