A popular medium enables people who want to influence public opinion to air their views. Authorities, journalists, politicians and scientists spread their message on Twitter, Facebook and blogs. Governments publish websites and use YouTube to promote good behaviour.

In the sixteenth century, they published broadsheets, pamphlets, ordinances and indulgences to exert control and to inform the population. Government publications in the sixteenth century and political and religious leaders on Twitter today: they send and you receive.