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Mastodon monoculture problem

Niestety, polskie tłumaczenie nie jest dostepne. Wyświetlono w języku: English.

Recent moves by Eugen Rochko (known as Gargron on fedi), the CEO of Mastodon-the-non-profit and lead developer of Mastodon-the-software, got some people worried about the outsized influence Mastodon (the software project and the non-profit) has on the rest of the Fediverse.

Good. We should be worried.

Mastodon-the-software is used by far by the most people on fedi. The biggest instance,, is home to over 200.000 active accounts as of this writing. This is roughly 1/10th of the whole Fediverse, on a single instance. Worse, Mastodon-the-software is often identified as the whole social network, obscuring the fact that Fediverse is a much broader system comprised of a much more diverse software.

This has poor consequences now, and it might have worse consequences later. What also really bothers me is that I have seen some of this before.

As seen on OStatus-verse

Years ago, I had an account on a precursor to the Fediverse. It was based mainly around StatusNet-the-software (since renamed as GNU social) and the OStatus protocol. The biggest instance by far was — where I had my account. There was also a bunch of other instances, and there were other software projects that also implemented OStatus — notably, Friendica.

For the purpose of this blogpost, let’s call that social network “OStatus-verse”.

Compared to the Fediverse today, OStatus-verse was miniscule. I do not have specific numbers, but my pull-numbers-out-of-thin-air rough estimate is, say, ~100.000 to ~200.000 active accounts on a very good day (if you have the actual numbers, do tell and I will gladly update this blogpost). I do not have exact the numbers for either, but my rough estimate is that it had between 10.000 and 20.000 active accounts.

So, around 1/10th of the entire social network.

OStatus-verse was small but lively. There were discussions, threads, and hashtags. It had groups a decade before Mastodon-the-software-project implemented groups. It had (desktop) apps — I still miss the usability of Choqok! And after a bit of nagging I was even able to convince a Polish ministry to have official presence there. As far as I know this is the earliest example of a government-level institution having an official account on a free-software-run, decentralized social network.


Then one day, Evan Prodromou, the administrator of (and the original creator of StatusNet-the-software), decided to redeploy it as a new service, The new software was supposed to be better and leaner. A new protocol was created because OStatus had very real limitations.

There was just one snag: that new protocol was incompatible with the rest of OStatus-verse. It tore the heart out of that social network.

People with accounts lost their connections on all OStatus-compatible instances. People with accounts on other instances lost contact with people on, some of whom were pretty popular in OStatus-verse (sounds familiar?..).

It turned out that if an instance is 1/10th of the whole social network, a lot of social connections lead through it. Even though other instances existed, suddenly a huge chunk of active users just vanished. Many groups fell mostly silent. Even if one had an account on a different instance, and contacts on other instances, a lot of familiar faces just disappeared. I stopped using it soon after that.

From my perspective, this single action set us back at least five if not ten years as far as promoting decentralized social media is concerned. Redeployment of fractured the OStatus-verse not just in the social connections sense, but also in the protocol and developer community sense. As pettter, a fellow OStatus-verse veteran put it:

I think a bit of nuance on the huge-blow thing is that it didn’t only impact by cutting social connections, but also in protocol fragmentation, and in fragmenting developer efforts into rebuilding basic blocks of a federated social web time and again. Perhaps it was a necessary step to them come back together in designing AP, but personally I don’t think so.

Of course, Evan had all the right to do that. It was a service he ran, pro bono, on his own terms, with his own money. But that does not change the fact that it crippled the OStatus-verse.

I believe we need to learn from this history. Once we do, we should be worried about the sheer size We should be worried by the apparent monoculture of Mastodon-the-software on the Fediverse. And we should also be worried about identifying all of Fediverse with just “Mastodon”.

Cost of going big

There are real costs and real risks related to going as big as has. Those costs and especially those risks are both to that instance itself, and to the broader Fediverse.

Moderation on the Fediverse is largely instance-centric. A single gigantic instance is difficult to moderate effectively, especially if it has registrations open (as currently does). As the flagship instance, promoted directly in official mobile apps, it draws a lot of new registrations — including quite a few problematic ones.

At the same time, this also makes it more difficult for admins and moderators of other instances to make moderation decisions about

If an admin of a different instance decides’s moderation is lacking for whatever reason, should they silence it or even defederate from it (as some already have, apparently), thus denying members of their instance access to a lot of popular people who have accounts there? Or should they keep that access, risking exposing their own community to potentially harmful actions?

The sheer size of makes any such decision of another instance immediately a huge deal. This is a form of power: “sure, you can defederate from us if you don’t like how we moderate, but it would be a shame if people on your instance lost access to 1/10th of the whole fedi!” As GoToSocial’s site puts it:

We also don’t believe that flagship instances with thousands and thousands of users are very good for the Fediverse, since they tend towards centralization and can easily become ‘too big to block’.

Mind you, I am not saying this power dynamic is consciously and purposefully exploited! But it undeniably exists.

Being a gigantic flagship instance also means is more likely to be a target of malicious actions. On multiple occasions over the last few months it found itself under DDoS, for example. A couple of times it went down because of it. Resilience of a federated system relies on removing large points of failure, and is a huge one today.

The size of that instance and it being a juicy target also means that certain hard choices need to be made. For example, due to being a likely target of DDoS, it is now behind Fastly. This is a problem from the privacy perspective, and from the perspective of centralization of Internet infrastructure. It is also a problem that smaller instances avoid completely by simply being smaller and thus less interesting targets for anyone to take down with a DDoS.

Apparent monoculture

While the Fediverse is not exactly a monoculture, it is too close to being one for comfort. Mastodon-the-non-profit has outsized influence on all of fedi. This makes things tense for people using the social network, developers of Mastodon-the-software and other instance software projects, and instance admins.

Mastodon is neither the only instance software project on fedi, nor the first. For example, Friendica has been around for a decade and a half, long before Mastodon-the-software got it’s first git commit. There are Friendica instances (e.g. operating today within Fediverse which had been part of the OStatus-verse a decade ago!

But calling all of Fediverse “Mastodon” makes it seem as if only Mastodon-the-software exists on the Fediverse. This leads people to demand features to be added to Mastodon and to ask for changes that have sometimes already been implemented by other instance software. Calckey already has quote-toots. Friendica has threaded conversations and text formatting.

Identifying Mastodon with the whole fedi is also bad for Mastodon-the-software developers. They find themselves under pressure to implement features that might not entirely fit with Mastodon-the-software. Or, they find themselves dealing with two groups of vocal users, one demanding a certain feature, other insisting it does not get implemented as too big of a change. Many of such situations could probably be more easily dealt with by clearly drawing a line, and pointing people to other instance software that might fit their use-case better.

Finally, Mastodon is currently by far (measured by active users, and by number of instances) the most popular implementation of the ActivityPub protocol. Every implementation has its quirks. With time, and with new features being implemented, Mastodon’s implementation might have to drift further away from the strict spec. It’s tempting, after all: why go through an arduous process of standardizing any protocol extensions if you’re the biggest kid on the block anyway?

If that happens, will every other implementation have to follow it, thus drifting along with it but without actual agency in what changes to the de facto spec are implemented? Will that create more tensions between Mastodon-the-software developers and developers of other instance software projects?

The best solution to “Mastodon misses feature X” is not always “Mastodon should implement feature X.” Often it might be better to just use a different instance software, better suited for a particular task or community. Or to work on a protocol extension that would allow a particularly popular feature to be reliably implemented by as many instances as possible.

But that can only work if it’s clear to everyone that Mastodon is only a part of a bigger social network: the Fediverse. And that we already do have a lot of choice as far as instance software is concerned, and as far as individual instances are concerned, and as far as mobile apps are concerned.

Sadly, that seems to go against recent decisions by Eugen, which go towards a pretty top-down (not quite vertically integrated, but gravitating towards that) model of official Mastodon mobile apps promoting the flagship instance. And that is something to worry about, in my opinion.

A better way

I want to be clear I am not arguing here for freezing Mastodon development and never implementing any new features. I also agree that the signup process needs to be better and more streamlined than it had been before, and that plenty of UI/UX changes need be implemented. But all this can and should be done in a way that improves resilience of the Fediverse, instead of undermining it.

Broader changes

My laundry list for broader needed changes to Mastodon and the Fediverse would be:

  1. Close registrations on, now
    It is already too big and too much of a risk for the rest of the Fediverse.
  2. Make profile migration even easier, also across different instance types
    On Mastodon, profile migration currently only moves followers. Who you follow, bookmarks, block and mute lists can be moved manually. Posts and lists cannot be moved — and that’s a big problem for a lot of people, keeping them tied to the first instance they signed-up for. It’s not insurmountable — I had moved my profile twice and found it perfectly fine. But it is too much friction. Some other instance software projects are working on allowing post migrations too, thankfully. But it’s not going to be a quick and easy fix, as ActivityPub design makes it very hard to move posts between instances.
  3. By default, official apps should offer new people a random instance out of a small list of verified ones
    At least some of these promoted instances should not be controlled by Mastodon-the-non-profit. Ideally, some instances should run different instance software as long as it uses compatible client API.

What can I do myself?

And here are things we ourselves can do, as people using the Fediverse:

  1. Consider moving off of if you have an account there.
    That’s admittedly a big step, but also something you can do that most directly helps fix the situation. I had migrated years ago, and never looked back.
  2. Consider using an instance based on a different software project
    The more people migrate to instances using other instance software than Mastodon-the-software, the more balanced and resilient Fediverse we get. Hearing a lot of positive opinions about Calckey, for example. GoToSocial is also looking interesting.
  3. Remember that Fediverse is more than just Mastodon
    Language matters. When talking about the Fediverse, calling it “Mastodon” is only making the issues I mention above more difficult to deal with.
  4. If you can, support projects other than the official Mastodon ones
    At this point Mastodon-the-software project has a lot of contributors, a stable development team, and enough solid funding to continue safely for a long while. That’s great! But same cannot be said about other fedi-adjacent projects, including independent mobile apps or instance software. In order to have a diverse, resilient Fediverse, we need to make sure these projects are also supported, including financially.

Closing thoughts

First of all, the Fediverse is a much more resilient, more long-term viable, safer, and more democratized social network than any centralized walled garden. Even with its Mastodon monoculture problem, it is still not (and can’t be) owned or controlled by any single company or person. I also feel that it is a better, safer choice than social networks that only cosplay decentralization and pay lip service to it, like BlueSky.

In a very meaningful way, OStatus-verse can be said to have been an early version of the Fediverse; as noted before, some instances that had been part of it then are still running and part of the Fediverse today. In other words, Fediverse had been around for a decade and a half by now, and survived the Identipocalypse even as it got badly hurt by it, while observing both the birth and the untimely passing of Google+.

I do believe Fediverse is leaps and bounds more resilient today than OStatus-verse had been before the redeploy. It’s an order of magnitude (at least) larger in terms of user base. There are dozens of different instance software projects and tens of thousands active instances. There are also serious institutions invested in its future. We should not be panicking over all I wrote above. But I do think we should be worried.

I do not attribute malice to recent actions of Eugen (like making official Mastodon apps funnel new people towards, nor to past actions of Evan (redeploying on And I don’t think anyone should. This stuff is hard, and we’re all learning as we go, trying to do our best with the limited time we have available and restricted resources in our hands.

Evan went on to be one of the main creators of ActivityPub, the protocol the Fediverse runs on. Eugen had started Mastodon-the-software project in the first place which I strongly believe allowed Fediverse to flourish into what it is today. I really appreciate their work, and recognize that it’s impossible to do anything in social media space without someone having opinions on it.

That does not mean, however, we cannot scrutinize these decisions and should not have these opinions.

Update: I did a silly; is behind Fastly, not CloudFlare, of course. Fixed, thank you to those who poked me about it!

Update 2: Heartfelt thanks to Jorge Maldonado Ventura for providing a Spanish translation of this blogpost, published under CC BY-SA 4.0. ¡Gracias!