No. It's a discussion forum, yes, but I don't count such as "social media" the same as facebook or twitter or etc. in part because both the membership and discussion are curated rather than open to all.
More to the point, while in my view posting to a forum is certainly c
ommunication it's not
social interaction, mostly because there's no here-and-now to it - no face-to-face or even voices over a phone/voip/whatever. I mean, for all you know username "Lanefan" could just be a robot with some sentence construction skills and a well-functioning "old school" subroutine always running.
Now if all of us were gathered in a pub somewhere over a beer, THAT would be social interaction!