This paper presents two case studies of informal group communication using multimedia conferencing that supports various media including video, audio and chat. The studies provide a comparison of audio and chat as communication medium and present data on usage patterns, user preferences and attitudes. The quantitative and qualitative data collected suggest that chat does have advantages in some situations when used for informal communication along with video. The results provide evidence against the hypothesis that chat is a low bandwidth alternative only used when audio communication is unavailable. This suggests that video mediated chat deserves further attention from designers and the research community, since it is often ignored as a “useful” scenario Categories and Subject Descriptors H.3.3 [Communications Applications]: Computer conferencing, teleconferencing and videoconferencing. H.5.5 [Group and Organization Interfaces] Computer-supported cooperative work. General Terms P...