@gruber Sure, and what's the service?
It's as much the Fediverse as it is Mastodon.
After all, you *can* run Mastodon without the Fediverse. Essentially, that's what Truth Social is.
Further, another thought for you: while Mastodon is the main service people are using now, what will happen when Tumblr joins the Fediverse? Or Flickr? Or Post? That's going to happen this year!
Or what will happen if there's a user migration from Instagram—like there just was with Twitter? That's feasible!