As a focus of study, ‘social media’ tend to lack definitional clarity and grounding in theories of media and text. This paper establishes and discusses a conceptual framework for defining social media as communicative genres, constituted by the interplay between interactive functionalities configured at the software level and the invocation and appropriation of various software functionalities to achieve specific purposes in and through users’ actual communicative practices. I suggest that social media might be seen as particularly dynamic genres, subject to continuous disruption and uncertainty,owing to their deinstitutionalised and participatory character, and the shifting roles of producers and recipients in the networks and conversations that make up social media content.