looking cute :-)
may I suggest a couple of small tweaks?
Mastodon/ActivityPub comes across as more accurate to me. Mastodon is built on top of ActivityPub, not the other way round.
the other point is "recently"; IIRC the term Fediverse was in use before Mastodon and even before ActivityPub. maybe the reference could be retained to some extent, while making it accurate, with "or as we've long taken to calling it"