The Fediverse is a network of thousands of independent social media servers of many different kinds.
The most popular kind is Mastodon, but it wasn't the first and isn't the only one. Some of the accounts you interact with are on other server types, e.g. @Iancylkowski is on Pixelfed and @theatticdwellers is on PeerTube. There are many Fediverse server types:
Whichever type you're signed up on, they connect together to form a social network called the Fediverse.
@feditips@mstdn.social
You omitted #calckey from the list. We're like Mastodon, but with bells and whistles
I can't eat my honey for the tears!
Whoops! I've added it in now.
@feditips@mstdn.social aww, thanks Foxy. You're ace.
Although, I also admire your polkadot duck