A concurrent revolution in communications technologies is radically changing our lifestyles and forms of social and political engagement in ways that are challenging the status quo. These hybrid forms (forums and space) and network power are pointing the way to a new conception of the city. As financial crisis, public sector cuts and changing demographics restrict the ability to deliver jobs and services, new forms of social innovation, collaborative capacity building and co-production are emerging. By harnessing the collective capacity of many diverse individuals, organisations and communities of interest through self-organising initiatives, the socially innovative city is one that is able to generate appropriate responses to changing needs and opportunities and turn them into action via a new form of collaborative urbanism.