During crisis more than ever, the principle of the invisible hand on the social media[En crise plus que jamais, le principe de la main invisible sur les médias sociaux]

Social media are more and more important in citizen's life nowadays. The trend is more and more clear with more young people who use various social media several times during the day. Naturally, times of crisis don't make an exception. The main social media record peak of connection during major events: floods, attacks, snow episodesi… On the social media, authorities (mayors, prefects, emergency services, law enforcement…) can find information. But they also can give instructions to the population. On their side, it is the citizens who put information there. It is also the citizens who are awaiting information and instruction of authorities on social medias. Thus, the social media are a vast place of information exchange, where each can find elements about the situation and give some information that he wants to share. But, there is all the same a problem. Indeed, the authorities often have a reluctance to open accounts on the social media and to set up a real interaction with citizens during crises. Mainly because they think that there are only rumors on the social media during a major eventii. Based on this observation, this article suggests demonstrating that there is a system of invisible hand on social media. This invisible hand is activated by the mass of account which interact on the social media, and take care of their own regulation. Thus, in the first time, we shall approach the behavior of the users on the social media and the social capitaliii search. Then, we shall see the phenomenon of fake news and finally we can explain the action of the invisible handiv on social media. The purpose of this article will be to ally the theory about this invisible hand and some real fact observed during crisisv. The ambition of this article is to demystify the use of social media, to establish the fact that there are not only rumors which circulates there and that an authority can find concrete and operational information there. It will be necessary to remain careful and to explain that this social media monitoring can't be improvised, but that it have to be prepared before a crisis. Finally, this article can open a reflection about VOST, Volunteer's Operational Support Team, which help the authorities during crises… i