The Open University in the UK delivers distance learning to its students. Traditionally, the students study independently of one another. With the aim of enhancing interactions and collaborations amongst students, two post-graduate courses introduced authentic, collaborative activities. This is easier to achieve now because of the availability of the wiki tool: a lightweight, web-based collaborative authoring environment. This article examines the effect of the wikis' functionality on the students' use of the tool, and the consequences of their engagement with one another and with the activities, and the learning opportunities offered by the use of wiki. This is a relatively large-scale study involving 56 wikis produced by over 250 students. The data were drawn from the two courses using a variety of research methods. A qualitative inductive analysis of the interview data was conducted to look for emergent themes in the data. The emergent themes were validated by cross-referencing the recorded comments in the wikis and course forums. We found that the limited functionality of wikis influenced how students engaged with the collaborative activities. Although all groups were able to author collaboratively the documents required for assessment, they did not always perceive the learning benefits intended by the course teams. This article expands upon our earlier research which highlighted the role of a dedicated discussion tool to complement a wiki when used in collaborative activities. This article will be of interest to academics aspiring to employ wikis on their courses and to practitioners who wish to realise the potential of wikis in facilitating information sharing and fostering collaboration within teams.