User models are abstract representations of user properties including their needs, preferences, knowledge, as well as physical, cognitive, and behavioral characteristics. These characteristics are usually represented by variables. User models are instantiated by the declaration of these variables for a particular user or group of users. Such instances of user models are called user profiles. A user profile captures the kind of information about an individual user that is considered by an adaptive system to adapt to aspects of a certain situation and preferences of different users.

Complimentarily the process of user modelling can be applied to enhance the accessibility of user interfaces by generating or adapting them according to the particular user needs and preferences represented in the user profiles. In spite of the different approaches in this area, further research and development is necessary, particularly in addressing the need for standards to support the interoperability and portability of user models across implementations. More specifically, one of the main challenges of user modelling is the lack of a common approach for integrating user profiles that support different user models within individual implementations, and for migrating profiles from one implementation to another. This can be attributed to the broad variety of user profiles and the incompatibilities that can occur among them. For example, differences in user profiles can occur due to differences in scope of the modelling, source of information for the modelling, time sensitivity and update methods of the model (static vs. dynamic model). In this paper a thorough review of the latest developments in the area of user modelling for accessibility is presented. Further, in the core of the paper future potentials and challenges that this technology has to face in order to gain significant traction and adoption from wider audiences is analyzed.