Prior research has shown that EFL learners who wrote collaboratively with partners using wikis improved the content quality and language accuracy of their L2 individual writing more than students who wrote individually. Drawing on the dataset from Hsu and Lo's study, the current study explores the nature of the students' collaborative dialogue that occurred during wiki collaborative writing and the potential link between wiki collaboration and development in individual L2 writing. The students, working in self-selected groups, collaboratively completed a writing task with two drafts via wikis. Wiki pages created by the students, including the comments, discussion and history modules, were analysed for the occurrence of content-, organization- and language-related episodes. The total number, focus and resolution of the episodes were tallied and analysed. Results of the quantitative and qualitative analyses showed that (1) students produced significantly more language-related episodes than content-related and organization- related ones, (2) organization-related episodes occurred the least frequently, (3) students were able to resolve the majority of the content-, organization-, and language-related issues successfully and (4) students demonstrated a preference to work with grammar over lexis during wiki-mediated collaborative writing process. The results are discussed in the light of Hsu and Lo's study. Theoretical and pedagogical implications are discussed.