A relevant application using the social network concept is described in this article in the IEEE Pervasive Computing Journal:Social Networks as Health Feedback Displays by Margaret E. Morris from Intel (September/October 2005 (Vol. 9, No. 5) pp. 29-37):
Social networks have thus far served primarily as analytic tools for social scientists. Leveraging pervasive computing, this new research transforms social-network models into behavioral feedback displays. These ambient displays, which reflect data on remote and face-to-face interaction gathered by wireless sensor networks, were intended to raise awareness of social connectedness as a dynamic and controllable aspect of well-being. An interdisciplinary health technology research group at Intel recently developed and tested prototypes in the homes of older adults and their caregivers. This article reviews the psychological rationale for the project and highlights some reactions of participants to the displays.
Why do I blog this? I think it's an highly pertinent and innovative usage of such technique!