On social media, you take the floor and share your opinion. You enter into debate with supporters and opponents of your ideas. Such discussions can change society. As a result, top-down decisions are sometimes reversed or adjusted.
In this context, a picture is worth a thousand words. Photos of the Arab Spring or the refugee crisis are shared massively. They influence emotions and beliefs.
Five centuries ago, printed books had the same impact. Luther wrote short pamphlets that were produced in one day, while his opponents did the same. They made the presses roll, started revolutions and divided the world in supporters and adversaries.