The question is, how does one keep tabs on which communities and instances are part of Meta?
I admittedly am new to this all, but it seems like a kind of take over that could happen quietly, ending us up in a situation similar to what we see now with reddit but even more confusing for the average user.
Communities: Basically impossible, unless Meta/Facebook has a public list somewhere.
Instances: That will be public, because they have to register the domain somewhere and I'll also assume that they will actually want people to know which ones are theirs, so their users join those.
Oh there’s a list of all their known domains and a mastodon bot that keeps track of new ones. I run my own mastodon instance and I have everything preemptively blocked.