Stories are shared by millions of people online every day. They post and re-post interactions as they re-tell and respond to large-scale mediated events. These stories are important as they can bring people together, or polarise them in opposing groups. Narratives Online explores this new genre - the shared story - and uses carefully chosen case-studies to illustrate the complex processes of sharing as they are shaped by four international social media contexts: Wikipedia, Facebook, Twitter and YouTube. Building on discourse analytic research, Ruth Page develops a new framework - 'Mediated Narrative Analysis' - to address the large scale, multimodal nature of online narratives, helping researchers interpret the micro- and macro-level politics that are played out in computer-mediated communication.