Abstract In this paper, I present a data-intensive approach to conversational informatics. It not only brings about quantitative understanding, permitting us to turn a great accumulation of keen observations into a pile of computational models, but also helps to build conversational agents by virtue of recent progress in machine learning and data mining. The topics include a smart conversation space for allowing people to engage in conversation in a cyber-physical space, conversational interaction capture for conversation modeling and content production, learning by imitation for producing conversational interactions, cognitive design for understanding mental processes of conversational actors, and synthetic evidential study for collaborative study on understanding social processes.