As I understand it, Firefish/Calckey is a fork of Misskey, and both are microblogging so I presume they’re Twitter-inspired but it has a much richer feature set so I’m not really sure of its “inspiration lineage”. Maybe it’s a clone of something else but I just don’t use social media enough to know.
Also, I just realized I actually have a Misskey account rather than a Firefish/Calckey account. I’m that clueless lol
But yeah I’m definitely enjoying the fediverse. It’s proving to be both a useful place to find info and a fun place to just hang out and chat!