> However, I disagree with some of the analysis, and have a couple specific points to correct.

[cwebber@social.coop]

Here's our story:
- We have 26 users: [Alice, Bob, Carol, ... Zack].
- Each user sends one message per day, which is intended to have one recipient. (This may sound unrealistic, but it's fine for modeling.)
- Each user sends a message in a ring: Alice => Bob, Bob => Carol, ... Zack => Alice

[cwebber@social.coop]

Now just before you say "wait but ATProto isn't for DMs", yes, but one way this could happen is that eg Bob follows Alice, Carol follows Bob, etc.

What I'm saying is, messages can have an "intended audience". That's what we're using here.

[cwebber@social.coop]

Before we get into this, remember, the main difference between "message passing" and the "shared heap" is the former has directed and delivered messages, the latter does not. See prev blogpost for explainer.

So, what happens in a day for both systems? Because that's what we really want to find out.

[cwebber@social.coop]

Under message passing, Alice sends her message to Bob. Only Bob need *receive* the message. So on and so forth.

- For an individual self-hosted node, messages passed per day: 1.
- Per the decentralized network, total messages passed zooming out: 26.

That's about what we'd expect.

[cwebber@social.coop]

Under the public-gods-eye-view-shared-heap model, each user must know of all messages to know what may be relevant. Each user must *receive* all messages.
- Individual self-hosted server, 26 messages must be received per day.
- Zoom out on whole decentralized network: 26*26: 676!

[cwebber@social.coop]

Sounds survivable with 26 users though, right?
Let's try just adding 5 more users.

Message passing:
- Per node per day: no change.
- Per the network: 5 more messages.

Public gods-eye-view-shared-heap-model:
- Per node per day: 5 more per day
- Per network: ((31 * 31) - (26 * 26)): 285!

[gkrnours@mastodon.gamedev.place]

@cwebber wait, caffeine is an alternative to ADHD medication?

[cwebber@social.coop]

Now, could we handle a million self hosted users? Is it possible? No problem in message passing. EXPLOSIVE with atproto.

What if we had a million users and added just 5 more? How many more messages must the network bear?

5 new messages in message passing.
*10,000,025* new messages sent in atproto!

[cwebber@social.coop]

"Christine that's ridiculous, we're not expecting a million self-hosted users"

Well I think it would be nice!

But regardless, ActivityPub has 27,000 servers on it, all meaningfully participating in the network.

ATProto, in its current design, would be crushed to DEATH

[cwebber@social.coop]

"But Christine", you may say, "I heard gossip might fix this!"

No. It cannot.

In fact, I was being more generous than a gossip network, and assumed you only *received* a message once.

With gossip you might *receive* more than once.

But you need to receive a message to know it.

[darius@friend.camp]

@cwebber I am as you know on your side in all this but there are people I disagree with who argue that having an incomplete view of all messages globally on ActivityPub is not "meaningfully participating" and I have trouble articulating my position with these people. Feels like a dead end where persuasion is highly unlikely

[cwebber@social.coop]

ATProto was designed for a "big world" view. That's fine! But I'm trying to show seriously what happens if it was actually, really decentralized.

*Every* fully participating node added to the network makes the network explosively more expensive.

ATProto doesn't scale towards decentralization.

[cwebber@social.coop]

In other words, the public god's-eye-view allows for a pantheon, but not a civilization. You can only have so many gods who see all.

An important characteristic of a decentralized system is scoping what you *don't* need to know.

This wasn't in the design goals of ATProto, and it has effects.

[blort@social.tchncs.de]

@cwebber

To me the *ideal* is for *everyone* who uses social media to either self host or to be hosted by someone they know and trust personally. Even a tiny fraction of this would be far, far more than a million users!

Will we get there? Who knows? Few would have predicted that we would even get to where we are now, and numbers are only growing...

#Fediverse #SelfHosting #SocialMedia

[cwebber@social.coop]

I may be coming across as some academic computer science nerd. It's actually the opposite. I'm a humanities nerd who cares about the agency of users so much I've twisted myself into a shape where I can do a computer science thing.

But architecture matters. It affects the worlds we can have.

[cwebber@social.coop]

This is what I say when I say that Bluesky's goals of "credible exit" may be reasonable, but it's not decentralized. There is no getting around the fact that the system, as designed, is designed for a few large players. Small players can play on the *periphery*, but they can't play the big game.

[cwebber@social.coop]

Now, you might think, maybe ATProto could fix this!

And it can.

And the solution, ultimately, will end up looking... a lot like ActivityPub.

[cwebber@social.coop]

The point is that nearly everyone knows at this point that "sure, Bluesky is centralized today, in practice!" But a lot of the responses I see are "but decentralization is just around the corner thanks to ATProto!"

So that's why I'm writing this out.

[fleeky@prsm.space]

@cwebber one thing I am surprised no one has mentioned.. the very philosophy of a gods eye view is inherently a centralizing one ?

[cwebber@social.coop]

Well, that's it. We've reached as far as we're going tonight.

There's still a bit left, a bit of reframing about what I am and am not concerned about with decentralized identity, and then a bigger topic about Bluesky's design goals vs community expectations. Then we'll talk talk about values.