We propose that the advent and ubiquity of new media tools and social networking resources provide a means for professional, networked learning to "scale up." We preface our discussion with a review of research that has led us to argue for professional learning communities, document the policies and practices of professional development in high-achieving countries internationally that have transformed the way teachers learn, and discuss online social networking as it is being used for teacher learning. Our 10-year experience at the Carnegie Foundation for the Advancement of Teaching gave us an opportunity to learn to make multimedia representations of practice for use in both preservice and professional development. We believe that making practice public in this way can be transformative.