While technically true, I think calling Mastodon the smallest amongst them is a little indigenous. After all, wasn’t the idea of ActivityPub “protocols, not platforms”?
For me personally, Mastodon opened me to the world of federated social media, and I’m now hosting my own AP-based single-user social media page running GoToSocial. My usage won’t add to Mastodon’s MAU’s count, but 90% of my interactions are with Mastodon users, and I think that’s the beauty of the system.
Nah I like the idea of Facebook finding a little island of tech nerds who worship some god call 'ActivityPubbinus' and proceed to whip the foreign colonialists with CAT6 cables.
I guess for now it's misleading more than anything, as they say it's the smallest of the three major federated platforms. That's hardly precise as neither Threads nor Bluesky is federated yet.
Bluesky should federate at the end of the month though, and a bridge to activitypub is already ready. Interesting times ahead.