In their Introduction to 'Décrire la conversation en ligne', the editors consider the macro-question: “What have we learnt since 1999 about conversations and ways to describe them?” In this chapter, by contrast, we address the question at a micro-level: “What does the literature tell us about our particular object of study and how do insights from multimodality and research on computer-mediated conversations help us to structure the way we approach the analysis?” The object of study in this volume is a technology-mediated multimodal conversation between two native speakers of different languages, carried out for educational purposes and captured as a screen-video. For language learners, Web-based conversations offer the opportunity to develop second language fluency and literacy in a purposeful, motivated way within a familiar environment of online networking. For language teachers, it offers a potential arena for structured, semi-structured and unstructured interactions for language learning, but for planned activities to be motivating and successful, they must to some extent conform to the developing style of communicative behaviour that characterises online communication. With a sharp focus on a 6’41”data extract taken from the data resource introduced earlier in this volume, the aim of this chapter is to reflect on the challenges of analysing how the students use multiple modes of communication in the multi-media orchestration of their online conversation. As a technology-mediated social event, the multimodal conversation studied here engages us with issues of mediation and socialisation. As a piece of educational data, it invites scrutiny of learning processes and outcomes with a view to identifying successful dynamics for online learning dialogues. As a video recorded event, it presents us with issues of data representation. We now address all these aspects as reflected in the literature.