@evan finally, when we compare Facebook's move with ActivityPub to Google, we seldom compare it to E-mail. We compare it to XMPP, which got extinguished by Google Talk defederation.

Even more finally: analogy is not an argument. While arguing with people who use analogy as an argument, it's more sound to point that out rather than finding a counter-analogy which may or may not be analogous enough. 🙂