Everyone is focused on the Fediverse ActivityPub conversation, but I'm finding it equally fascinating, maybe even more interesting, how Mastodon makes it super easy to have alternate web front-ends that are purely static HTML+JS, like pinafore.social and elk.zone.
Much safer to try these tools than, say, try an alternate ActivityPub host. As these "front-end APIs" become more powerful (and I hope they do), we might see more innovation on this front.