With more than two billion users worldwide, Facebook is often described in popular media as the ‘largest country in the world’, due to its nature, size and composition. However, Facebook is a company, regulated primarily as a business. The aim of this project is to raise and answer key questions about Facebook’s normative practices, and particularly about the site’s regulation. My argument is that, throughout its short history, Facebook’s users have regulated the site. User regulation is described as the practices of criticism, negotiation and rejection to which Facebook’s architecture, policies and practices are subjected by its users and non-users, and the subsequent impacts of such regulation on Facebook. User regulation of Facebook is an informal, arbitrary process that leads to Facebook’s continuously evolving norms and reflects the persistent struggle for control between Facebook and its users. A pluralistic, digital-cultures approach has been adopted in the theoretical and conceptual framework of this thesis, with an emphasis on the canons of media and communication, cultural studies and political economy. Multiple case studies of user regulation are presented to explain the dynamics of how users are regulating the architecture, policies and practices of the site, in order to demonstrate that users are regulating Facebook. The first part of the thesis begins with an exposition of the user regulation model, after which a framework for Facebook, its users and user regulation is presented. Subsequently, the methodology, the efficacy of the methodology and the case study approach are discussed. The second part of the thesis explores three interrelated themes – privacy, advertising and labour on Facebook – to explain and demonstrate my argument. These three themes are key to explaining the process and phenomenon of user regulation, as they constitute what I term the ‘circle of exploitation’ on Facebook. In the third part of the thesis, resolutions to this circle of exploitation are addressed by proposing certain alternatives, in order to examine the ability and vulnerability of users. Finally, the key outcomes of this project and my research agenda of providing a historical account for future research into the ontology and epistemology of Facebook are considered.