To fulfill user acceptance, a hot spot for database systems are user preferences. Preferences are an adequate model to represent situation dependent scenarios, user groups (personalization) and even individuals (individualization). The model makes an impact on modelling of social roles, too. One of our prototypes implements the roles of seller and buyer. Roles modelled by preferences are an efficient means to select just the information you need to fulfill your job. You get the information you are interested in and the information is presented in a situation aware manner to meet just the point.