The COREU network is a little-studied but vitally important instrument of EU foreign policy, which in 2010 distributed nearly 8.500 messages on EU foreign policy to the 27 member states, the General Secretariat of the Council and the European Commission. This article presents an overview of its functioning and an analysis of its role, taking into account the creation of the European External Action Service. It argues that the COREU network has made it possible to achieve more cooperation on matters of EU foreign policy than would otherwise have been possible, by creating a "thick virtual soup" of information within which officials based both in capitals and in Brussels can more easily participate in EU foreign-policy cooperation. After summarizing the COREU's early history, the article describes how the circulation of messages is currently organized and traces the spectacular rise and partial fall in numbers of COREU messages through EPC/CFSP. It then analyses how COREU messages contribute to the policy cycle of EU foreign policy and go beyond the remit of CFSP to include national foreign policies. Finally, the article shows how the system pre-dates the more recent surge in Brussels-based actors and has been a necessary condition for it, by tracing the development of the Political Committee/Political and Security Committee.