This volume discusses "online" communities, where work is mediated and supported by a computer network. How do people react to spending much of their life online? What impacts does it have on the organization for productivity? This volume addresses these key issues by analyzing prototype systems of today that can help answer these important questions for tomorrow. This volume will be of interest to those involved in the applications and social impacts of computer-mediated communications systems and their design and evaluation including managers who must decide whether to implement such systems. It is also relevant for those interested in the relationship between technological innovation and social change.