Part 1. Building communities of library users Picking a platform and finding a voice / Lisa Bunker From broadcast to conversation in an academic library / Laura Little, Andrew Lopez, Jessica McCullough, Rebecca Parmer Find us on Facebook : the evolution of social media at a community college library / Dana A. Knott and Angel M. Gondek Social media and healthcare : building and sustaining communities for patients and providers / Patricia J. Devine Adding value with advertising : using paid promotions to build your online community / Chris Chan and Joanna Hare Part 2. Building communities of library professionals Building communities of practice in the library profession / Katie Elson Anderson Building a personal learning network / Stony Evans Part 3. Transforming community into action--social media and social justice The urgency and agency of #OccupyNassau : actively archiving anti-racism at Princeton / Jarrett M. Drake Cultivating critical dialogue on Twitter / April M. Hathcock