FB is a handy thing for organising bike rides, walks etc. And for being in various groups about things I’m interested in. Never really been able to understand the “My life is so much better since I deleted Facebook” idea. Guess it depends how you use it.
Don’t use Twitter or Instagram. Nothing against them, just never felt the urge to join.
This place is my main social media use though. I even use it for bike related stuff at times (yeah, controversial, I know!).
Strava is good too. Been a long time since I chased any KoMs but is very handy for storing what I’ve done. And I like seeing what friends have been doing.
Oh and not sure if it’s really social media, but I do love YouTube. So much brilliant, useful, useless, trivial, interesting, obscure, niche, funny stuff on there.