Abstract
There is a multitude of systems in the area of mobile and pervasive social computing providing and using social context for pervasive interaction between persons. Currently, it is hard to distinguish the different approaches as there is no appropriate taxonomy available yet. In this paper we introduce the STIP taxonomy to define social context in the area of social computing and further propose to use the term Situated Social Context for a more focused subset of social context for pervasive social computing. We elaborate the taxonomy with a small survey of mobile social networking systems and discuss future research challenges.