Inspired by a European project, PHEME, that requires the close analysis of Twitter-based conversations in order to look at the spread of rumors via social media, this article has two objectives. The rst of these is to take the analysis of microblogs back to rst principles and lay out what microblog analysis should look like as a foundational program of work. The other is to describe how this is of fundamental relevance to human-computer interaction’s interest in grasping the constitution of people’s interactions with technology within the social order. Our critical nding is that, despite some surface similarities, Twitter-based conversa- tions are a wholly distinct social phenomenon requiring an independent analysis that treats them as unique phenomena in their own right, rather than as another species of conversation that can be handled within the framework of existing conversation analysis. This motivates the argument that microblog analysis be established as a foundationally independent program, examining the organizational characteristics of mi- croblogging from the ground up. We articulate how aspects of this approach have already begun to shape our design activities within the PHEME project.