A friend, in a locked post, talked about leaving Facebook because of their manipulation of what you see. "That's a lot of power for one company to wield", the person said. I wrote the following in a comment:
I was never comfortable with Facebook. I had an account for about two minutes, under the belief that if I created and then deleted an account, nobody else would be able to create a fake account to impersonate me. Ah, those days of naivete.
I don't trust platforms that give me a selective view of activity without letting me turn the knobs. On Dreamwidth (and LiveJournal before it turned evil), I know that if I read back until I hit something I recognized, I've seen everything on my subscription list (modulo author-deleted posts). I wasn't going to miss stuff. On Facebook, and Twitter and Google+, that isn't/wasn't true. Twitter now has a control for "show me stuff in order" versus "show me selections based on what's likely to interest me", but I don't know that the former doesn't also filter stuff out. I use Twitter, but knowing that I can't rely on it for consuming stuff. For the people I want to see everything from, I get notifications. That doesn't scale, so I miss a lot, and therefore it's not reliable. But I'm there because that's where some important-to-me connections are, presumably like why you were on Facebook.
Not being on Facebook has cut me off from some stuff, I know. Too many people think "well, I posted it on Facebook so you should know about it". I can only hope that, now that more people are becoming aware of how Facebook filters content out, some people might stop assuming that. We'll see.
When you use someone else's platform you're at risk of them flaking out or changing their rules or them just being dishonest. Facebook, Twitter, Stack Exchange, Reddit, LiveJournal... they control the servers so, ultimately, they control your activity. They can be arbitrary (recently saw someone get booted without appeal from Twitter for content that their algorithm said was bad, that wasn't), they can be capricious (Stack Exchange, need we say more?), they can be evil (LiveJournal, now in thrall to the Russian government)... we make the best decisions we can at the time about where to participate, and sometimes learn we were wrong and have to move.
But striking out on your own has costs too. If you set up a blog on your own, a few of your friends will subscribe by RSS but you won't have the community aspect. When LJ imploded I didn't set up my own blog; I moved to Dreamwidth. I decided to trust Dreamwidth, and believe they are more worthy of that trust than LJ was. I like to think that Codidact is more worthy of trust than Stack Exchange is, and that people can participate with more confidence that they won't be treated sneakily and viciously. Disclosure: I'm one of the people in charge at Codidact, so I'm biased. But operating in the open and not having stockholders makes a big difference too, I think.
If we want to be part of Internet-connected communities, whether small groups of friends or huge international groups, then we have to either build our own platforms or rely on others. Usually the former is impractical, so it comes down to remaining vigilant about the practices of the providers on whom we depend. And sometimes we need to pick up and move (or leave), disruptive as it is.