I have to agree on this being both and the obvious answers were pointed out by @fullcoverbetting and @davemccoy in addition to what you have said.
According to Google search the definition of social media is
websites and applications that enable users to create and share content or to participate in social networking.
That speaks clearly for itself. We socialize and interact thus creating a network. Blogging is within the context of social media.
We have the same mindset on many things @leeart. :) The definition does put steemit into the social media realm.