In the context of the question:
How does the message differ, depending on the medium?
Imagine a platform placed at Stationsplein in front of Rotterdam Centraal station. There is a loudspeaker, which I can grab whenever I want, and shout my personal views, opinions, and everything else that comes to my mind. If that happens, it might draw the attention of a small audience which would gather from time to time, gossiping, clapping or jeering. Such a situation would seem like a spectacle for consumption in the style of reality TV talent shows. It is certain though that this could not be a central part of my daily activity.
On social media platforms, this is often the case, except that the views, preferences and personal experiences are stored as data to be processed, presented on electronic “walls” and not on real-world platforms. The Internet creates a sense of private communication since it happens with the help of individual devices in private or public spaces. The information displayed may not be needed or would better not be published.