Interesting question. I tend to say “no.” Medium strikes me as more similar to Flickr or YouTube (which I also do not consider social media). The difference with these platforms is that the content shared is clearly valuable in and of itself, like a well-crafted video or composed photograph. The text, photos and video on social media, on the other hand, hardly ever qualify as artistic contributions and therefore I hardly consider their authors ‘creators.’ I feel that they are quite different, although the reasons in my head are not fully fleshed out, I admit.