The multiple meanings of fediverse

Sometimes, there are words where everyone thinks they know what it means, and also, that everyone else also has the same idea of what it means. But then it turns out that terms like 'fediverse' can have surprisingly vague edges. If someone talks about the fediverse to you, it's easy to imagine a cluster of Mastodon servers that are talking to each other, with some added Pixelfed, Misskey and Lemmy servers added on top. It's good enough for most conversations, but there are some surprising questions that can pop up, once you start to peel at the definition. Do you include that one specific Mastodon server as part of the fediverse? Or what about this software that's not a social network, but still has some sort of ActivityPub integration? Answers to these questions might always not be so easy.

Wikipedia's definition provides a good start, which says: "The fediverse is a group of federated social networks that allow users of a service to communicate with users of the other services, typically using the ActivityPub protocol."

This definition gets the idea across fairly well. However, there are multiple meanings of the word fediverse, that mainly from the boundaries of the network, and how large people imagine the network to be. Defining those boundaries might be more complicated than people expect, however. In this article I look at three different ways people can interpret the term fediverse: by focusing on either Community, ActivityPub, or Interoperability. In every interpretation there is a 'core' part of the fediverse that everyone agrees on that it is a part of the fediverse. The edge cases is where it gets interesting, fuzzy, and where people will disagree with each other.

One note before we start: the term fediverse has an interesting history as well, which I'm not touching upon in this piece. If this is something you're interested in, I recommend this piece by WeDistribute.

Community

In the interpretation of fediverse as a community of connected servers, the focus is on which servers are actually connected with each other. Servers that could theoretically connect with the rest of the network, but are largely not doing so (because they are blocked by many servers, for example) are often interpreted as not being a part of the fediverse. The fediverse is seen as having a specific culture and norms, and servers who are not part of this culture are actively resisted from becoming part of the fediverse.

A clear example of this is the fedipact, where people have signed up to proactively block Threads when they implement ActivityPub. When people talk about Threads joining the fediverse being bad for community, safety or moderation, this is a prescriptive view of the fediverse, where the fediverse ought to be a group of social networking servers that share common values. Because they see Threads and Meta as not living up to those values, they push back against Threads joining the fediverse.

This view also explains some of the harsh pushback people voiced when the Stanford research on CSAM on Mastodon was released. People felt like "their" fediverse was under attack for stuff that happened on activity that was not part of their network. A post with a high engagement was fairly explicit in this, saying: "the fediverse as you know it is absolutely NOT a fucking hub of CSAM". Even though the Stanford report found CSAM material on servers that fall within the top 10 Mastodon servers in size, these servers are perceived as being outside of the network and the fediverse.

A generalised, rough definition of this interpretation of fediverse would be 'all ActivityPub servers, minus the servers that are on the T0 block list'. The T0 block list is the block list that gets recommended for new admins to block the worst of the worst servers (such as kiwifarms and other extremist hate group servers). This definition gives a rough general direction, but is not fully accurate, and it should be assumed that everyone has a slightly different idea of which servers to include and exclude.

ActivityPub

Another form of describing the fediverse is by focusing on the underlying protocol, ActivityPub. In this view, all platforms, servers and projects that connect with each other using ActivityPub are part of the fediverse. This is a fairly straightforward definition, and more commonly used among developers. When you are building new software for the fediverse, you are mainly interested in making sure that the communication with other fediverse software works correctly.

The focus on ActivityPub does result in stretching the definition of social networks. For example, Castopod is a podcast hosting platform. It uses ActivityPub to allow people on other ActivityPub platforms to interact (comment, like, share) with the podcasts. Castopod explicitly defines itself as part of the fediverse. When people talk about social networks, they often think of feeds that show posts of other people, whether that is in short text form (microblogging), pictures (Instagram, Pixelfed) or video (TikTok). Castopod does integrate with a social network, but the software itself is not necessarily a social network.

This means that in this understanding of the word fediverse, software can become part of a social network by integrating with the ActivityPub protocol.

Interoperability

The third approach is to focus on the interoperability that the open protocol of the fediverse allows. If you can fully interact in both ways with someone else, that means they can also be seen as part of the fediverse. For example, most people who are using Mastodon are mainly interested in being able to follow their friends, read their posts and send replies, which their friends can also read. They are less interested in whether their friend uses Friendica, Firefish or Akkoma, as long as it all just works. Earlier this year, Axbom posted a picture as an explainer of what the fediverse is, which seemed to show this position. Their visualisation showed ActivityPub as the largest 'tree', but also included other networks, such as diaspora* and Matrix.