This paper describes a design experiment in which we attempted to develop a knowledge building community for participants attending a graduate course in two distant sites. Students in two cohorts—at Simon Fraser University and The University of Hong Kong—participated in a joint course on knowledge building. To support the discourse, we used weekly classes at both sites, a shared Knowledge Forum database, virtual visitations, and video conferences. Using Bielaczac and Collins’ (1999) framework of learning community, we a) discuss the characteristics and evolution of the knowledge building community; b) illustrate how we could Identify and assess knowledge building in online contributions; and c) examine how different modalities of the learning environment support and sustain the development of the community.