This presentation examines how the widespread adoption of social media as journalistic tool has shaped news audiences on these platforms, determining which stories are shared and whether social media users form publics around particular sources or themes. Drawing on social media data around Australian news media – including Twitter and Facebook activity – the presentation evaluates how the centralization of social media impacts upon how audiences engage with news online. Rather than discussions and commentary being shared across individually-run and dispersed blogs, the presence of audience, journalists, and editors alike on the same social media platforms allows for both a clear idea of what is being shared online, but also why and how audiences are doing this. The presentation shows how this centralization means that journalists themselves act as both promoter and audience, involved in the sharing and dissemination of their own stories and also interacting with other sources and their audiences.