Do We Need Awhereness? Finding the Answers with SocioXensor G.H. (Henri) ter Hofte 1 , Ingrid Mulder 1 , Joke Kort 2 1 Telematica Instituut, the Netherlands 2 TNO Information and Communication Technology, The Netherlands {Henri.terHofte, Ingrid.Mulder}@telin.nl, Joke.Kort@tno.nl Abstract. Mobile devices tend to travel along with people wherever they are and whatever they are doing, and consequently enter various social contexts of that person. This literally puts these devices in an ideal position to capture several aspects of social phenomena, including location of a person and proximity to others. We are currently designing and implementing SocioXensor, an extensible toolkit that exploits the hardware sensors and software capabilities of contemporary mobile devices like PDAs and smartphones to capture objective data about human behaviour and their social context (e.g., location, proximity and communication), together with objective data about application usage and highly subjective data about user experience (e.g., needs, frustrations, and other feelings). Thus, we provide the social sciences with a research instrument to gain a much deeper, detailed, and dynamic insight into these phenomena and their relations, which in turn can inform the design of successful context-sensitive applications. In particular, SocioXensor allows researchers to obtain indicators for the value of location relative to the value of other types of context information. Introduction Man is a social being, continuously and dynamically adapting to his social context, and increasingly supported by advances in mobile technology. Current research into context-sensitive applications stresses the relevance of using context information in applications in order to improve desirable properties such as social translucence (see for example, [3,8]). The massive success of context-mediating