Collaborative learning can be seen as a collection of perspectives based on principles of interpersonal interaction. In computer-supported collaborative learning (CSCL), issues of how students collaborate to solve problems in technology rich environments are in focus. Studies focused on the use- and mediation of technological tools for communication, collaboration and problem solving are beginning to provide us with an understanding of collaborative interaction. In this talk I will present a state-of-the-art look at the challenges of collaborative learning in virtual environments, focussing in particular on situations where learners are geographically distributed.