In this article we study how members of an interdisciplinary research team use an online forum for communicating about their research project. We use the concepts of "community of practice" and "connectivity" to consider the online interaction within a wider question of how people from different academic traditions "do" interdisciplinarity. The online forum for this Grey and Pleasant Land project did not take off as hoped, even after a series of interventions and amendments, and we consider what the barriers were and how they might be overcome. Barriers to involvement included participants' expectations of interaction and collaboration--expectation that real interaction happens elsewhere, tensions between academic discourse and forum talk norms, unfamiliarity with the technology, and different conceptions of appropriate academic discussion. We suggest that common academic practice does not prepare us well for creating interdisciplinary research communities through online collaboration tools, whereas such tools are our best bet currently for including geographically dispersed members in collaborative projects. Therefore, careful planning and competence building would be necessary if such tools are to be used in collaborative research. Suggested interventions, based on our experience, include providing a more focused forum, making technical support easily available, and setting up particular tasks or items to debate, within a preset, synchronous timeframe, focusing on issues relevant to the project at that time.