The last twenty five years have seen a small revolution in our approach to the understanding of new technology. It has become a founding assumption of CSCW that in the future, if not already, most computer applications will be socially embedded in the sense that they will become infrastructures for the development of the social practices which they are designed to support. This will be true in an ever increasing variety of domains and living conditions. Assuming that IT artifacts have to be understood in this socio-technical way, traditional design criteria in CS (performance, correctness, stability or usability) need to be supplemented by methods and perspectives which illuminate the way in which technology and practice are mutually elaborating.