I used to use reddit, I have moved all my presence over here. That's about it.
I have a FB Messenger account because that is how a lot of my family keeps in touch with me, and I have this. I had a proper FB account back when I was in uni and Facebook was still only for uni students, but I think I dropped it shortly after that.
It's not some grand principled stance, I just don't get most of them because I am apparently an old man. Like Instagram, why do I want to share pictures with just random people? How am I networking with anybody by doing so? I honestly don't get why it is so popular.
Same. Except I still occasionally use reddit, just not as much as I used to.
I only use FB messenger as it's big here for communication and FB to post photos of my kids for my family to see which has only been recently, since I had kids. Before that I didn't even touch FB.
Other than that, social media doesn't interest me at all.