Facebook is launching an ActivityPub service to compete with Mastodon. There's a lot of talk in the webs about locking them out. Big words but not much power behind them. They will, in an instant, have millions more users than the existing ActivityPub services will, so the question really is -- who's being locked out? It was never a good bet that the architecture of ActivityPub would somehow be able to resist Silicon Valley-scale social networks. That doesn't mean there are no answers, just that bluster isn't one of them. You have to think.