I’d just like to interject for a moment. What you’re referring to as Mastodon, is in fact, ActivityPub/Mastodon, or as I’ve recently taken to calling it, ActivityPub plus Mastodon. Mastodon is not an service unto itself, but rather another free component of a fully functioning Fediverse made useful by the W3C core protocols and other vital components etc. etc.
@Edent Thank you! I was waiting for this joke and I don’t think anyone could have had better delivery:)