Lemmy and Kbin
The rapid rise of Lemmy and Kbin, dubbed the 'threadiverse', have altered the dynamic in the fediverse. A look at how this changes the structure and the dynamic of the fediverse at large.

The fediverse has rapidly changed over the last few weeks. With the rapid growth of Kbin and Lemmy, a new way of communicating and forming social communities has gained prominence. As a result of changes to Reddit's API, and a subsequint revolt by the users, many people are looking for alternatives, and finding them in Lemmy and Kbin. People have started to call the Lemmy and Kbin section of the fediverse the 'threadiverse', and dubbed it the #redditmigration. There's quite a few impacts out of this development, but first lets get into what's actually happening
A short background
Lemmy is a link aggregator and discussion platform that has been around for a few years, it joined the fediverse in late 2020. It is reasonably similar to Reddit in it's core ideas: it has up/down votes, centred around communities (subreddits) where people can submit content to. These submissions can be either links or text, and people can posts comments to them.
Lemmy has been fairly insulated from the rest of the fediverse until recently, even though interaction is possible. Part of it seems to be that one of the biggest instances is explicitly a 'tankie' instance, and the flagship instance (lemmy.ml) federates with them. This created a situation where the front-page of lemmy.ml showed a lot of content that would not necessirely appeal to a broader public.
Meanwhile, Kbin is an even newer project that started early 2023. It is also a link aggregator centred around communities (called magazines), and has extra microblogging functionality as well. The main instance, kbin.social came online in April, and had a few hundred users, before the Reddit migration started. The project by @ernest was still actively being worked on, and advertised itself as a 'very early beta'.
The impact
The are multiple ways to look at the impact of the #redditmigration to the threadiverse on the rest of the fediverse:
The most obvious aspect is simply that of growth. The migration brings in new users, and also a different type of users. Fedidb added a specific section showing statistics about the threadiverse, and it shows the dramatic growth. The total accounts went from 50k to 180k in less than 2 weeks time. For Kbin the growth is even more dramatic: Kbin went from 300 users on June 12th to over 30k less than a week later. This is especially impactful for Kbin, where the project was expected to handle a few hundred users that were testing the service while it was being developed, and now suddenly it has to handle a massive inflow of people that expect a fully featured service.
This growth comes from a different group of people, people who aren't necessarily interested in microblogging. Redditors use social networks in a different way than people on Twitter do, and they bring these habits and expectations with them to the fediverse. People understandably get frustrated when tech news uses the term Mastodon as a stand-in for the fediverse at large. While incorrect, it is understandable that mainstream audiences often aren't aware of projects existing in the fediverse beyond Mastodon. Now this dynamic is shifting. Media reporting on the issues with Reddit now mention fediverse alternatives like Lemmy and Kbin. This helps change the dynamics of the language around Mastodon and fediverse.
Lemmy and Kbin also represent a different way of interacting with the fediverse. Microblogging on Mastodon, photo sharing on Pixelfed and tracking books on Bookwyrm are all centred around people. You follow individuals you find interesting, and read the content they share. The threadiverse instead is framed around topics and communities with shared interests. Just like on Reddit, the primary interaction is based on the content, the links posted, and the comments placed. You can interact with communities on Lemmy, Kbin or Reddit, without taking a look at the usernames of the people who are posting, and just taking in all the content. Your experience on the link aggregators gets better when you start recognising people, and interact with them specifically to form social bonds. However, it is significantly less important than it is on microblogging platforms. There, you mainly start by following people, and then based on the people you follow, you read about the topics you might find interesting. How these different approaches interact with each other is something that will play out in the future, but there is some interesting potential here, especially in Kbin. Kbin also allows for microblogging, but links it to the magazine, allowing you to scroll through short microblog posts from people who are part of the magazine community.
Overall, the sudden and rapid rise of Lemmy and Kbin is changing the structure and culture of the fediverse. How this will develop further into the future remains to be seen, and worth watching.
EDIT 26-06: Developer Ernest provided a correction, stating that work on Kbin started much earlier. Early 2023 is when the project moved to Codebase and became more serious.