Paid protesters? A supposedly "citizen" interest group, but founded and financed by a private company? A letter of opinion, self-generated without your knowledge, bearing your signature? These are examples of astroturfing, a communication strategy whose real source is concealed and which wrongly claims to be of citizen origin. The word citizen, symbolizing public opinion in the eyes of many, enjoys great credibility within societies. Several actors thus decide to assume it, hoping to achieve their communication goals more easily. This type of fraud, not new, is on the rise thanks to the Web. This book reveals 99 cases of astroturfing that have been denounced over the last 25 years. Their analysis provides a portrait of these strategies, their initiators, their objectives, their targets and the means of communication used. Used as much by private companies as by political parties and governments, astroturfing influences public, media and political agendas, giving it a leading role in corporate governance. Because astroturfing corrupts the public space and undermines the deliberative process inherent in the creation of public opinion, it is important to know, recognize and denounce it.