I would like to give an update on "federation" on Bluesky.

mcc

Imagine a hypothetical comic artist, "Gertrude". One day a hypothetical podcaster named "Louis CK" dies, and "Gertrude" posts something rude about this. Bluesky bans her. She's now deleted from the Bluesky PDS, blocked from the Bluesky relay and appview. Say, hypothetically, that virtually everyone agrees this was a bad moderation decision.

But Bluesky is decentralized, so we don't have to use the Bluesky PDS, relay, moderation service, or appview! We can Credibly Exit! Right? Right? (1/3)

mcc

I (me, mcc) never trusted Bluesky, so I've been self-hosting my own PDS from the start. I've been happily using blacksky.community for the last month (since Bluesky started gating access to their appview/web frontend on clicking to agree to a new TOS that seemed to me sketchy). Hypothetically, "Gertrude" could do the same. She can join Northsky PDS, make posts through Zeppelin, and Bluesky blocks her but Blacksky just fetches the posts from her PDS for me, and I get to read them.

Right? (2/3)

mcc

No. Because "Gertrude", in our hypothetical, *won't bother making those posts*. Because the vast, incredible, overwhelming majority of Bluesky users are still on the Bluesky network, and she is excommunicated. She *could* cultivate a group of followers who all use the Northsky infrastructure just so they can see her posts. But she could also cultivate a following on her Patreon. So Hypothetical Gertrude ignores Bluesky, posts to Patreon, and her Patreon posts get *shared* to Bluesky. (3/3)

mcc

And that's why I say, TLDR:

- I am legitimately excited about the work being done by Blacksky Algorithms! I am using their frontend and happy with it.

- Northsky is an interesting development to watch

- If you're on a Bluesky PDS, I recommend migrating off with one of these tools https://bsky.app/profile/did:plc:ii5jchdzlmcojjw4dqczcgkh/post/3lyt6t6qfa22u

- Everything Sucks. A LOT of things would have to change at a social level for *any* entity other than Bluesky to have power or independence in the ATP ecosystem. I still don't trust Bluesky.

George B

@mcc

May be a stupid question but I don't know enough about ATProto, ActivityPub or Bluesky infrastructure to be sure

Would it be possible for one of those systems that is forking Bluesky to make it so they use both ATProto and ActivityPub streams so they can be on here without a bridge?

mcc

@gbargoud Sure. You could do that. I'm aware of a patch to the PDS (backend) software that allows it to flat out publish via ActivityPub. I haven't seen a *frontend* that merges the streams yet though.

There's also the problem that you can't reeeallly monitor *just part* of the Bluesky network. To follow part of it you're supposed to drink the entire firehose and filter out the parts you care about.

mcc

As an update since posting the above thread I have received replies from two people, one saying I am underestimating the level of stack coverage Blacksky has, another saying I am overestimating it. Also a "AppView" and "Client" are different. Sorry.

The stack is just so tall! There are *so many* layers in this protocol's model. And it seems like every single one of them is an opportunity to introduce censorship

mcc

Update: Rudy who operates blacksky.community responded to this thread on bluesky. Above I said I wasn't clear on how independent Blacksky was of the Bluesky infra. His answer is "completely". They run their own relay (which scrapes PDSes itself), the relay feeds into their own appview, the appview feeds into their own client. https://bsky.app/profile/rude1.blacksky.team/post/3lyv5rwpc722c

And since they bridge end-to-end, in my Hypothetical Example above, they *could* choose to make different moderation decisions from Bluesky PBC.

mcc

So. The thread above. An update.

We finally got a live test of the "Gertrude scenario", when a popular Blacksky user got permbanned by Bluesky. I, using my own PDS and blacksky's website, can't see him or his posts ( https://blacksky.community/profile/did:plc:2aebn3xk5t63net43eeepire/post/3m2iokicegs2b ). What gives?

A lot of people claim this is because Blacksky really is using Bluesky's appview, and gave me a way to verify this looking at headers. This seems to contradict Rudy's previous claims. I've asked Rudy for clarification: https://bsky.app/profile/did:plc:2aebn3xk5t63net43eeepire/post/3m2jve23cf22m

mcc

Follow up, 2025-12-27: Rudy here confirms the Blacksky appview is still being worked on (eg: blacksky uses bluesky's appview still)

https://bsky.app/profile/rude1.blacksky.team/post/3maykethsbk24

The sticking point, as he describes it, is "backfill". This alludes to the issue that makes me compare ATProto to blockchain: to get the features users expect, every node on the network must mirror the network's entire history. This is impractical, which is why bluesky is as of this moment a federated network with effectively only one node.

mcc

:frogsiren: BLUESKY HAS OFFICIALLY NETSPLIT :frogsiren:

There has always been more than one Fediverse. Different instances make different moderation decisions so some instances can't see posts by some users.

There has only ever been one Bluesky because every ATProto frontend uses the same Appview.

It is January 2026 and that's no longer true; Blacksky's Appview is available for beta use and there is at least 1 user banned on Bluesky but not Blacksky. And vice versa.

https://bsky.app/profile/did:plc:w4xbfzo7kqfes5zb7r6qv3rw/post/3mcozwdhjos2b

May Likes Toronto

@mcc Would this mean that there'd be a new bridgy specifically to Blacksky?

Anuj Ahooja

@mayintoronto No - Bridgy Fed supports any ATProto PDS, including the ones run by Blacksky

@mcc

nimu εїз🖖🏻

@mcc for us tech noobies in the audience, could you explain what does this mean?

mcc

The "portable identity" elements of Bluesky/ATProto make the netsplit just a tad odd. My account is hosted on a PDS server I run, so I'm beholden to no frontend. If I log in through the main Blacksky frontend (Bluesky appview) one user I'm following shows only an error message. Via the Staging Blacksky frontend (atproto.africa), I can see I'm following him and see his posts. I'm SO curious about the edge cases. I assume if I boost him it's hidden from the Bluesky appview. What if I reply to him?

Fabrice Desré

@mcc When you are suspended by bluesky corp, is the ban at the app view or PDS level?

Fucking bitch Martin Vermeer

@quillmatiq @mayintoronto @mcc But what if I want to cancel the bridge, but only to the Nazi one? Can I do that, and advise my correspondents to migrate to BlackSky? How hard would that be?

Anuj Ahooja

@martinvermeer Not today, but stay tuned for next week

@mayintoronto @mcc

mcc

Oh and I can't get staging.blacksky on my phone app. So imagine if you were using Mastodon, but you saw a slightly different list of posters, *and potentially a different set of your own posts*, depending on whether you were using your PC or your phone. This is great if there's a banned user you want to follow— you get an *option* to follow them. Mastodon.social can deny me the *option* to follow someone, on Fediverse. But except in this edge case that *might* not be a fantastic user experience!

mcc

@coracinho Does this help? https://mastodon.social/@mcc/115918101156654032