Novice explanation (I’m the novice, not an expert dumbing it down). The Fediverse includes all platforms that operate on the ActivityPub protocol. That means that different platforms can be part of the fediverse. Mastodon is the biggest fediverse platform I’m aware of. It’s a lot like Twitter structurally. Even though Kbin looks like reddit and Mastodon looks like Twitter, they are all part of the fediverse because their built on ActivityPub. The way these platforms are built, anyone can make their own mastodon or Kbin instance (server) and Federate with other instances. Even though Kbin and Mastodon are pretty different, they can still federate with and talk to eachother.
Kbin and Lemmy are different software platforms that were both built to be a lot like reddit. They might even be hard to distinguish. They are written in different programming languages, so Kbin isn’t just another instance of Lemmy run by a different person, it’s a wholly seperate software project. However, they can communicate with eachother through ActivityPub. Since they look so similar to users, they almost look like they are just different instances to eachother, but under the hood it’s more like how Kbin can pull in microblogs from Mastodon.
Because Lemmy has been around a few years and Kbin only a couple of months, many developers are making Lemmy apps first. Since the software is made differently, an app made to work with Lemmy won’t necessarily work out of the box if you try to login with a Kbin account. But I do think that longterm there may be some apps that support both.
Novice explanation (I’m the novice, not an expert dumbing it down). The Fediverse includes all platforms that operate on the ActivityPub protocol. That means that different platforms can be part of the fediverse. Mastodon is the biggest fediverse platform I’m aware of. It’s a lot like Twitter structurally. Even though Kbin looks like reddit and Mastodon looks like Twitter, they are all part of the fediverse because their built on ActivityPub. The way these platforms are built, anyone can make their own mastodon or Kbin instance (server) and Federate with other instances. Even though Kbin and Mastodon are pretty different, they can still federate with and talk to eachother.
Kbin and Lemmy are different software platforms that were both built to be a lot like reddit. They might even be hard to distinguish. They are written in different programming languages, so Kbin isn’t just another instance of Lemmy run by a different person, it’s a wholly seperate software project. However, they can communicate with eachother through ActivityPub. Since they look so similar to users, they almost look like they are just different instances to eachother, but under the hood it’s more like how Kbin can pull in microblogs from Mastodon.
Because Lemmy has been around a few years and Kbin only a couple of months, many developers are making Lemmy apps first. Since the software is made differently, an app made to work with Lemmy won’t necessarily work out of the box if you try to login with a Kbin account. But I do think that longterm there may be some apps that support both.