Analyzing the activity of a group of students involved in an online university course with a simulation environment, this article considers and problematizes the idea of online community and its relations to learning. The analysis builds upon Dewey's conception of organic community and related perspectives. In valuing "joint action," such perspectives bury the relational nature of community construction under more concrete and stable notions of common mediating artifacts, geographic locations and membership among diverse communities. When the held-in-common is destabilized in the virtual, relations of student learning to community construction must be significantly reconceptualized. Moreover, for participants the meanings of "online" and "offline" activities and communities are interwoven within the process of interpretation, and should be understood as developing through this tension. Students and instructors alike face significant challenges in forging new online democratic learning environments. (Contains 4 notes.)