Social Media ist not just a way of communication, its a way of thinking, and by thus has in my eyes affected every part of society by now - with gradual differences regarding power. Even Hein Retter has been affected by social media, since ResearchGate is a social network.
1. Those who are not computer literate. 2. Those who are not using smart phone. 3. Mostly from villagers like farmers are labor. 4. Those educated but frustated with lots of irrelevant msgs. 5. Those who don't believe the msgs in social media. And so on.
But we all educated should invariably use social academic sites like research gate. Academia. Linkedin. Mendley. Etc. Popularise these websites to all academics and researchers. Good luck