Computer-mediated social groups, often known as virtual communities, are now giving rise to a more durable and more abstract phenomenon: the emergence of virtual institutions. These social institutions operating mostly online exhibit very interesting qualities. Their distributed, collaborative, low-cost and reactive nature makes them very useful. Yet they are also probably more fragile than classical institutions and in need of appropriate support mechanisms. We will analyze them as social institutions, and then resort to social contract theory to determine adequate support measures. We will argue that virtual institutions can be greatly helped by making explicit and publicly available online their norms, rules and procedures, so as to improve the collaboration between their members
