Context-awareness is a key feature of mobile and ubiquitous support (Abowd and Mynatt 2000). Also, context-awareness is supposed to partially solve usability issues of mobile support, as it can be used to ease the user’s interaction with the system. The most important context when supporting mobile users is their current location, observed by sensor data. It can be used to facilitate user interaction, e.g., by supplying default values for location-based services. At a closer look, the use of context has to be balanced carefully against other usability principles, as empirical studies of such systems reveal (Cheverst, Davies et al. 2001). Personalization is also a prevailing means to facilitate the use of mobile systems. Personalization too, at a closer look, poses usability issues that have to be carefully considered when designing a personalised, adaptive system. We discuss such concerns throughout the following sections 4 and 5.