It's like calling Slashdot social media. Or calling some phpbb forum social media. I mean, technically yes, but come on...
But yes, to me, a social network is something that focuses on people connecting with their friends on it, whereas the definition has expanded to "anything that involves people interacting with each other", which is... the whole Internet, basically?
@Dee I see your point, but if you cross into a "top 100" domain for traffic, I'd say that's significant enough to fall into a "social media" category, if you're open to the general public signing up.
@Dee Reddit is in the top 20, impressive... https://en.wikipedia.org/wiki/List_of_most_popular_websites