Internet-mediated intercultural discussions have been adopted for intercultural and second-language learning. However, the notion of community development in this context has received less attention. This study employs exchange structure (ES) analysis (Stubbs, M. (1983). "Discourse analysis." Oxford: Basil Blackwell) to investigate the dialogic process involved in the construction of a group-specific interactional pattern, identity, and activity within an online intercultural group. By identifying and tracking the shift of the ES and ES roles of each group, it explores how the members of each group constitute its internal activity and how the developed activity is related to intercultural learning. This study examines 14 groups of Japanese students and language learners from multicultural backgrounds who engaged in asynchronous online intercultural discussions for a 12-week period. The findings suggest that ES types and promoted intercultural learning vary among groups, develop implicitly, and are particularly influenced by frequent contributors. Furthermore, the data suggest that a certain type of ES encourages intercultural learning to move from knowledge exchanges to perspective changes. (Contains 6 figures and 6 tables.)