: After eleven years, CSCW is a well recognized research field which has generated, among other things, some new theoretical findings on work practices and cooperation and some new systems that are successfully applied by several organizations. The evaluation of successful applications from the point of view of the above recalled CSCW theories indicates some requirements (openness, continuity, contextualization and language-action integration) that the new generation of CSCW systems should satisfy. The prototype of the MILANO system is a working example of how those requirements can be met and of the challenges a full development of the CSCW potential poses to system designers and developers.