Who wrote 'The social contract?"

Jean-Jacques Rousseau

Government (1690) by Locke and The Social Contract (1762) by Jean-Jacques Rousseau (1712–78) proposed justifications of political association grounded in the newer political requirements of the age.

there is an explationation of this on a site called crash   course world history 1

new communications technology has affected the way social movements are organized because nowadays, social movements rely on social networks and the media to get different people with a similar way of thinking in contact, and thus, get them to mobilize for a greater cause.

individuals only participate in collective action when they feel identified with it. is in this aspect that social media becomes relevant, because it guarantees communication among all individuals and organizes the social actions that are going to be carried out, i.e., the social movements.

in addition, being covered by the media is important to validate the message and make it relevant in the social agenda, as well as to reach more people who can share interests, appealing to public sympathy for their cause.

in conclusion, it is by social networks and social media that social movement is given birth; by connecting different individuals with similar ideas and organizing them to mobilize for a greater cause.