I've avoided Facebook, but was coaxed into making an account just because some clubs now do all their communication on it. After a couple of weeks, when my only actions were innocuous posts like "nice specimen!" or "That's calcite", I was sent a message that I had violated community standards and my account was closed, with no recourse.

I get tired of telling people I'm not on Facebook, but not of staying off their surveillance system, nor of being captive to the whims of an algorithm. And I think it's sad that a lot of valuable information has been donated by people in good faith, embedded in a 'walled garden' which can disappear or be disabled at any time.