Adapting to user context, individual features and behavior patterns is a topic of great attention nowadays in the field of Web-based and mobile mediated platforms, such as eTraining, eCommerce, eLearning and so on. A challenge is to design an expressive ontology that is composed of human factors that can be used in any application, whether that is the WWW or any other embedded information system. Based on that ontology, engineers will design and develop personalized and adaptive interfaces and software. This will enable easy access to any content while being sufficiently flexible to handle changes in users’ context, perception and available resources, optimizing the content delivery while increasing their comprehension capabilities and satisfaction. Therefore, this paper describes a human factors ontology that has been positively evaluated, called UPPC (User Perceptual Preference Characteristics), and could be used in any computer mediated application for returning an optimized adaptive result to the user.