Knowledge management systems are used widely in many different organizations, yet there are few models and theories which can be used to help introduce and apply them successfully. In this paper, we analyze some of the more common problems for knowledge management systems. Using this background, we adapt models and theories from social and organizational psychology and computer supported collaborative work, and discuss a variety of different knowledge management systems in these contexts. We argue that knowledge management systems routinely adopt different social roles within an organization, and that these social roles can have a major in