This article analyzes co-regulation, by defining and exploring its recent institutional history in the Internet environment. It then assesses the legal definitions and taxonomies of co-regulation before constructing a 12-point scale of self-and coregulation. The term 'co-regulation' encompasses a range of different regulatory phenomena, which have in common the fact that the regulatory regime is made up of a complex interaction of general legislation and a self-regulatory body. Co-regulation has enriched conceptions of 'soft law' or 'governance' in the literature in the past ten years, but like those umbrella terms, refers to forms of hybrid regulation that do not meet the administrative and statute-based legitimacy of regulation, yet clearly perform some elements of public policy more than self-regulation, which is defined by the absence of formal roles for the nation-state or European law. Co-regulation is often identified with the rise of the 'new governance' in the 1990s. Recent European case law has seen a long overdue emphasis placed on human rights in judicial review of co-regulatory arrangements. Without regulation responsive to both the market and the need for constitutional protection of fundamental rights, Internet regulatory measures cannot be self-sustaining.