Group interaction, cooperation and collaboration, are not at all new in educational practice nor is the reflection on these phenomena a new invention in recent educational theories. From an educational viewpoint, computer support can just be seen as a new means to support old pedagogical ideas and approaches, also in group learning. However, the CSCL community is not the extension of a grown community of educational researchers defined by the new instrumental use of computers. Given its origin and evolution, CSCL research can -to a large extent- be characterized as applied cognitive science, which implies that computational models and theories belong to its foundations. Central concepts such as distributed intelligence, shared (external) representations or representational change can nowadays hardly be conceived without using the computer metaphor. So, the first "C" in CSCL stands not only for a technical means but also for a tool of thought, a metaphor or a conceptual device. In this sense, the new medium is a new message!
On this background, recent experience in several European projects will be presented and reflected. Special topics will be the design and practical implementation of computer-integrated spatial settings for cooperative learning, the practical use and the computational modeling of shared physical and virtual artifacts to support aspects of workflow in group learning, as well as the use of computational techniques to create a certain degree of awareness of group situations inside the machine. Finally, specific computational challenges set by the requirements of collaborative learning scenarios will be defined as an open agenda for future development.