In order to collaborate effectively in group discourse on a topic like mathematical patterns, group participants must organize their activities so that they have a shared understanding of the significance of their utterances, inscriptions and behaviors—adequate for sustaining productive interaction. The need for participants to coordinate their actions becomes particularly salient in dual-interaction environments, where, e.g., chat postings and graphical drawings must work together; analysts of such interactions must identify the subtle and complex ways in which meaning making proceeds. This paper considers the methodological requirements on analyzing interaction in dual-interaction environments by reviewing several exemplary CSCL studies. It reflects on the nature of social organization, grounding and indexicality that frame the interaction to be analyzed.