I'm being a bit cheeky in the article's tone but I am fairly confident from discussions in the past that "But where are Bluesky instances?" is a common question which usually demonstrates a misunderstanding of the architecture where "having instances of an app" is seen as a measure of decentralization.
My article was an attempt to dig at this specific misunderstanding by comparing it to "But where are Google Reader instances?" which I think illustrates its absurdity. I genuinely do think that the two pictures I provide close to the end clear this up in a way a lot of early atproto/ActivityPub discussions completely gloss over.
Re: Relays, I wrote here on why I didn't include them: https://news.ycombinator.com/item?id=48600963. They're kind of incidental perf optimizations rather than essential to the model. In the post, I wanted to focus on the model.
From my perspective, I care about the centralization/decentralization aspect a lot, and if I'm coming into the discussion with a much better understanding of the Mastodon side then _of course_ I'm going to ask about the instances--that's the vocabulary I'm going to use to try to probe for flaws and gaps. It's not necessarily that it's the instances specifically I care about, or that I'm somehow technically misguided.
What I hoped to read in the article is how we approach topics like centralization, censorship, moderation, data ownership--and with a technical lens. But I feel like all I got was "here's why instances are the wrong vocabulary" without substantively talking about the part I personally care about and want to marry the technical understanding with. Maybe I just read too shallowly and need to sit with it.
I see! That's a huge topic by itself since you're raising a lot of questions. Maybe this could be a different article. My aim with this one was just to clarify the network topology because it is a prerequisite to having the other discussion, and too often that prerequisite is not there.
If you ask a list of specific questions, that would help a lot. I might be able to write something or reply inline here.
I felt the same: when folks ask this question they might not be using the correct terminology, but what they actually want to know is how many different PDSes (that's what you mean by "atproto hostings", right?) there are in a typical feed.
I appreciate that a lot! The article has a deliberate and explicit scope, and covers it well.
I'm hoping that perhaps my personal perspective shades why "instances" comes up, or why the reaction on HN seems to include the wider scope than the article itself covers.
Thanks for the fair response, I agree you're being cheeky. Sorry, I'm being lazy not searching here, but have you written anything on if instances of something is a good measure of decentralisation? (FWIW, I feel independently owned/managed instances in the traditional non-mastodon-definition seems like an okay measure of decentralisation.)
I completely agree with the point in your link that relays are different to instances - I love architectures involving dumb-relay or zero-trust type nodes. But I think Relays should still be mentioned in your post, since they're probably the main architectural element which protect PDS instances from the scale issues heavily federated AP instances might face, right? (I only have a high level understanding of ATProto and very little experience with AP, happy to be told I just need to learn more for this to make sense.)
It's a comparison they are directly inviting, by constantly claiming it's decentralized. And then its defenders get upset when people rightfully point out that there is only a single instance, because that single instance going down takes the whole thing down. Like in Google Reader.
If atproto app goes down and it’s open source, anyone can put it back up with all public data intact.
Even if it’s not open source, anyone who wants to write the code can still get it back up with all public data intact.
I think it’s a substantial difference with “takes the whole thing down”. Can we acknowledge that?
if mastodon.social goes down, people would rightfully say that mastodon.social went down even though it's open source and anyone could run their own.
>"But where are all the Bluesky instances?"
I agree that it doesn't mean "atproto went down", and I don't mean to imply that. but "bluesky went down" is completely accurate, and bluesky is the one claiming to be decentralized due to using atproto. there are no other instances in bluesky's network, only partial ones (blacksky, last I heard they were still working on a major piece?), hence the "no it's not" responses.
I’m speaking about the hypothetical situation where an app is blown from the face of the earth, not temporarily goes down. I thought that’s what the parent discussion was about. I’m not sure what we’re discussing now.
All I’m saying is that if a developer forever takes down some atproto app, another developer can put up a new app that shows the old app’s data because the data is actually inside the users’ repositories. This is similar to how if Microsoft ever discontinued Word, you could still open Word documents in Google Docs. Does that make sense?
Re: Blacksky, they do fully run on their own infra now. So it doesn’t depend on Bluesky’s database.
"but where are the instances?" is asking "if Bluesky the company disappeared or turned evil, would there be a Bluesky network that kept going?".