Since this is the "fediverse", it makes much more sense to use general terms than things specific to a platform. There's already /kbin, and there may be other link aggregator software platforms that appear in the future, and having a standardised set of vocabulary that all platforms can use makes it much easier for everyone to understand.
/kbin calls them magazines and there's sometimes been some confusion over the term and Lemmy having communities, even though they are the same thing. All the microblogging platforms on the fediverse for example just have "posts" and "boosts", there is no specific term for them like "tweets" on Twitter (there was the "toot" thing for Mastodon for a while, but it was quickly rolled back and hasn't been official for several years).
Don't forget that when you post on Lemmy, you're not posting "to Lemmy", you're posting to the wider "fediverse".
A bit of back story on this: the Mastodon creator named them toots as a bit for celebrity attention, then, later, he renamed them to posts to be taken seriously. Now people on many different platforms call their posts toots, but post and status are equally valid (the status name comes from the api specification)
Hbomberguy, a leftie, YouTuber, offered to pay Eugen Rochko's development and hosting fees as long as Mastodon posts were called toots. Rochko accepted, not aware that toot can also mean fart (his first language is German). After Rochko realised this and had enough other income that he didn't have to rely on Hbomberguy, he reverted to the old name, but many users still call them toots because it's a more fun word.
Kbin magazines combine a ActivityPub Group ( what a Lemmy calls a "community") with a hashtag search, so they are a bit different than what's on Lemmy.
I just don't know that anyone's actually using the hashtag feed on kbin.
I had no idea. I think that's a great idea esp on new instances to help people get their feeds populated. I'm not sure what you mean when you say hashtag feed, though. Like, just when you search for a hashtag? It's there a way to follow a hashtag separate from a magazine. (Maybe that wouldn't be any different?)
Check out the Microblog tab. That's a stream of content from people using Mastodon/Misskey/Pleroma/etc. that isn't being sent to any groups. Kbin allows magazine admins to add hashtags to follow to the magazine, and those search for posts from that microblog stream that contain those hashtags.