Open-source software development projects are almost always collaborative and distributed. Despite the difficulties imposed by distance, these projects have managed to produce large, complex, and successful systems. However, there is still little known about how open-source teams manage their collaboration. In this paper we look at one aspect of this issue: how distributed developers maintain group awareness. We interviewed developers, read project communication, and looked at project artifacts from three successful open source projects. We found that distributed developers do need to maintain awareness of one another, and that they maintain both a general awareness of the entire team and more detailed knowledge of people that they plan to work with. Although there are several sources of information, this awareness is maintained primarily through text-based communication (mailing lists and chat systems). These textual channels have several characteristics that help to support the maintenance of awareness, as long as developers are committed to reading the lists and to making their project communication public.

Gestural communication is an important part of shared work, both in face-to-face settings and distributed environments. However, gestures in groupware are often difficult to see and interpret because of disruptions to their motion caused by network jitter. One way to improve the visibility of remote gestures is by using traces-visualizations of the last few moments' of a remote pointer's motion. We carried out an experiment to test the effectiveness of traces in helping people interpret gestures. We found that telepointer traces dramatically improved people's accuracy and confidence in their decisions as jitter delays grew larger. Our results suggest that telepointer traces and other visualizations of interaction history can be used to enrich communication among remote collaborators.