Abstract: This paper presents two conceptual models that we have developed for understanding ways that social media can support learning. One model relates to the “social” aspect of social media, describing the different ways that people can learn with and from each other, in one or more of three social forms: groups, networks and sets. The other model relates to the ‘media’ side of social media, describing how technologies are constructed and the roles that people play in creating and enacting them, treating them in terms of softness and hardness. The two models are complementary: neither provides a complete picture but, in combination, they help to explain how and why different uses of social media may succeed or fail and, as importantly, are intended to help us design learning activities that make most effective use of the technologies. We offer some suggestions as to how media used to support different social forms can be softened and hardened for different kinds of learning applications.