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Why care about backfilling?

Updated: at 11:19 PM

As outlined at length in a another post, backfilling isn’t working great in the Fediverse in general, and in Mastodon in particular. But why does it matter? Should you even care? I think so.

Table of contents

Open Table of contents

First some numbers to set the scene

Depending on what statistics you’ve decided to trust, the Fediverse has between 10-13 million registered users. Some Mastodon-centric statistics (laughably) claim that those are “Mastodon users”, but the truth is that the number is spread out over a multitude of Fediverse services, of which Mastodon un-arguably is the largest.

The number of the spread of users between the various Fediverse services, which is provided by FediDB, tell us that out of all the Fediverse users, 73% use Mastodon. Roughly 3 out of 4 accounts are Mastodon accounts. Between 7.3 - 9.5 million users, depending on who you trust to sum it all up. The caveat here is also that most of those 1 out of 4 who are theoretically not on Mastodon, quite likely have a Mastodon account as well. For example: I am not using Mastodon. Yet I have two separate Mastodon accounts (mostly for name grabbing and for testing). You can see the percentage split (of user accounts, not unique users) between the Top10 Fediverse services in this image:

Spread of users

If you decide to dig in to the numbers in more detail on FediDB, who counts Mastodon users to 7.3 million in total, you’ll notice that about 3 million of the Mastodon users (approx 41%) are using one of the Top6 largest instances, obviously with being the (by far) largest.

This also means that the other 11 195 Mastodon instances, out of a total of 11 201 instances, share the other 59% of Mastodon users. If those users were evenly spread out (they’re not) that’d mean 384 users/instance, which is tiny compared to the Top6 largest instances.

Let’s play some more with the numbers

So 1 out of 4 Fediverse users are having accounts on something that is not Mastodon. That is 2.7 million Fediverse accounts that are not Mastodon. In fact, there are 11 201 Mastodon instances, but there are also 16 268 other Fediverse instances out there. In total, 27 469 instances, according to FediDB.

That means that Mastodon instances are 40% or the total Fediverse instances. Lots of people are innovating (many because they are fed up with the limitations of Mastodon) and trying things out, possibly drawn to the Fediverse by the promise of federated decentralisation. Lots of people trying out some new cool flavour of micro-blogging, or inventing new stuff for podcasts or video/image sharing etc, or trying out Lemmy/kBin instead of Reddit etc.

I have two single-user instances, one running Akkoma and one running Friendica. In Friendica there is a statistics page that will show me (and now you) what “the world” (Fediverse) looks like, as far as it is concerned, and it looks like this:

Spread of instances

That page is actually quite long as it goes on to present statistics for all of the platforms it knows about, but as you can see, my Friendica instance is only aware of approximately 17k of the 25k total Fediverse instances. Still though, as far as my little instance is concerned, only 50% of the instances it does know of are Mastodon instances.

Back to backfilling

So, if we learnt in the other post that backfilling, which is basically “picking up posts” and “showing profiles” doesn’t work that well, particularly in Mastodon (the by far largest Fediverse service), but we also can see that outside the Top6 Mastodon instances (when counting user accounts) there are some 25 000 other instances, all of which will be rather small, that will have a problem to communicate with Mastodon for everyone who is outside those Top6 instances.

What happens is this:

Someone replies to your friends Mastodon post, and your friend is on, say, but you don’t follow that person making the reply, because you are on the instance. You will never see that reply. If your friend is asking a question, and he gets a correct response within 2 minutes from an instance that he nor you follow, you can spend hours discussing the topic, not knowing the correct answer is “right there”, and was given within minutes…but you can’t see it.

That is unfortunate both for you and your friend, sure. But how do you think the guy who gave the answer feels? He sees the discussion that keeps going, completely ignoring his correct answer, so he gives it again, with the same result. He is feeling ignored. As he sits there crying, wondering about the meaning of life in general and social media in particular, reminiscing on what could have been the start of a great friendship but it is shattered to pieces because… ok ok, shut up, skip the drama, but you get my point: it isn’t very social.

Mastodon follow request

To add insult to injury, this is what happens if you try to add a Mastodon user with “approve connections” (which is the sensible setting, as opposed to “open”) as a friend:

If the Mastodon user in question has “open” settings to add them as a friend they most likely have turned off notifications for friend requests too, on top of the default setting to not get notifications generated by people they don’t follow. In either case, both scenarios play nicely in to the Twitter/X refugees where having lots of followers is a mark of importance/glory/famous-ness/excellence so they don’t dig up the plebs that have added them as friends.

Whatever the strategy is (I’m not judging…much…), unless the Mastodon user on the big instance start adding friends from the new/small instances, they will not federate with it. That is just how it is.

The guys on the new/small instances must find friends that also add them as friends back, and do so with pretty much all the big instances out there, just to get federation going, as that is the only way to have a hope in hell that someone, anyone, will see their posts and replies.

Have I missed something? Am I unfair? Do you have opinions?
Feel free to send me a message.