Tech Report about designing multi-user location-aware applications
"The following paper provides developers, designers and researchers of location-aware applications with a descriptive framework of applications that convey Mutual Location-Awareness. These applications rely on ubiquitous computing systems to inform people on the whereabouts of significant others. The framework describes this as a 3 steps process made of a capturing, retrieval and delivery phase. For each of these phases, it presents the implications for the users in terms of interpretations of the information. Such framework is intended to both set the design space and research questions to be answered in the field of social location-aware applications."
The paper actually gives an overview of the main issues regarding location-based services, and more specifically multi-user location-aware applications/mobile social software.