Facebook remains off-limits for me (by choice, in case you were wondering). I have found it useful to install this browser extension, Impulse Blocker, and set it to prevent my browser from going there. Not because I am ever tempted, but because booby-trapped links are fairly common.
I tried a Mastodon site for a while but it did not suit me. I am not sure if that's down to Mastodon itself or this particular instance of it. I did not care for the local term for a posting. In my old-fashioned brain, a "toot" is quite a different utterance.
I am on Twitter and LinkedIn, more for professional purposes than anything else. And Reddit is an interesting place to discover new things. Reddit also hosts many passionate user communities of tech I use, which makes it a sometimes-OK place to get help. Some such "communities" can only mock people who don't already know the answers to the questions they ask. But "hey, it's worth a try" is my guiding principle in situations like that.
My microblogging platform of choice remains diaspora*. I moved my base in May from pluspora to diasp.org. Both are fully federated so the difference is really just technical. Pluspora went through a spell of reliability and performance issues, while diasp.org is solid so far.
Finally, this looks interesting: Minus. A social network where you get 100 posts for your lifetime limit. That'll keep the noise down, won't it? You'd think.