Health Communications is a first year course that was offered online for the first time during autumn term, 2004 using the learning management system, 'Blackboard'. One-hundred-and-seventy-seven students were enrolled in the course and they were placed into small workgroups. Four of the 37 group transcripts were selected; two groups possess high levels of interaction and the other two possess low levels of interaction. Each workgroup completed the set weekly activities. The online transcripts for week three were coded and analysed to compare and explore the following: (1) student engagement that facilitated the construction of learning and depth of learning (2) interactions with peers and teachers that facilitated learning and learning depth, and (3) aspects of the online environment that appear to have hindered or facilitated student engagement and interaction. Observable differences in the nature and depth of student learning are explained by the group dynamics and interactions. The interactive qualities of an effective learning group are revealed and include praise for discussions about tasks. For one group, attention to humour stimulated interaction though there was little evidence to indicate that it enhanced learning. Findings suggest it is important for teachers to direct, model and reinforce interactions that should lead to engagement with content and the construction of learning.