The studies focusing on social media are a bit dummy. I'm doing a PhD on the topic and I too feel like a dummy. Everyone has a different definition of social media, but we can't really generalize findings on all platforms. The studies should focus on services with their names, but then they would be less interesting. Are Twitter and Facebook the same? Can we generalize findings on one to another? No we can't. Besides, is HN a social media platform? Or Reddit? Talking about social media does not make much sense. It also hides out the fact that in the end everything is about the internet and digital content, together forming the new mass medium which is taking the world by storm.