The trend towards collaborative social software and technology in education appears to be exponential. The notion of ‘Web 2.0’ seems almost traditional in the face of aggregation tools and multi-platform spaces, intertwined by a proliferation of social networking tools. With the roll-out of ultrafast broadband and the imminent development of the Network for Learning in New Zealand, it is timely to consider the extent to which online social networks present both challenge and opportunity for educators’ professional learning. This study explores the experiences of educators using the VLN Groups network (www.vln.school.nz) to determine how far this user-generated mode of professional learning might extend professional practices in school. The study considers the ways and the extent to which the affordances of the VLN Groups social network site combine to affect educators' abilities to engage in effective professional learning. This interpretive study positions the findings within activity theory in order to characterise the actions of educators in the social network and to draw out tensions and opportunities for development. A literature review offers an overview of the field of online social networking in the context of educators' professional learning and outlines the challenges for integrating such informal, user-driven learning into meaningful student-focused professional development. A survey of members of the VLN Groups social network was conducted followed by interviews with four participants of the network. Findings highlight how the typical usage patterns of participants within the social network site reflect a growing familiarity with online ways of working, as well as opportunities to exploit this mode of professional learning more effectively. This study suggests that the VLN Groups can provide a thriving participatory system that enables educators to engage in an informal kind of professional learning focused on immediate concerns and contexts in their own teaching and leadership situations. It also raises questions related to what 'counts' as professional learning and how self-driven learning can be integrated into a cycle of active inquiry into practice. The study concludes by outlining recommendations for teachers, schools and policy makers related to connecting and coordinating professional learning in ways that maximise opportunities in the digital age.