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

[mcc@mastodon.social]

: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.

Rudy wants revolution. (@rude1.blacksky.team)

Bluesky runs an appview. Blacksky runs an appview. A complete appview is a several terabytes sized database of the >18 billion follows, likes and posts of all bsky users, ever and forever. To run a different appview is to make a fork in bsky’s timeline. One has new posts from Łink. One doesn’t.

Bluesky Social (bsky.app)

[greyduck@wellduck.me]

@mcc I haven't thought about the term 'netsplit' in AGES.

Also: Huh. Makes one wonder what Blewski's response will be.

[mayintoronto@beige.party]

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

[quillmatiq@mastodon.social]

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

@mcc

[coracinho@sunbeam.city]

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

[mcc@mastodon.social]

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@fosstodon.org]

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

[martinvermeer@fediscience.org]

@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?

[quillmatiq@mastodon.social]

@martinvermeer Not today, but stay tuned for next week

@mayintoronto @mcc

[mcc@mastodon.social]

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 that edge case this *might* not be a fantastic user experience!

[mcc@mastodon.social]

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

[mcc@mastodon.social]

@fabrice This is a VERY interesting question, as the answer appears to be "all of them". And when Link got banned, *that answer appeared to be surprising even to Bluesky employees*. The original messaging from Bluesky suggested you'd get banned only by the "labeler"— a third thing altogether. But there's obvious problems with that answer, and it's never what Bluesky implemented. After Link got banned Bluesky said they were reviewing this, but I don't think *changed* anything.

[mcc@mastodon.social]

@falken @coracinho Also the *way* in which Blacksky is making progress seems to me to make it look improbable any of the rest of us will reproduce what Blacksky has done. It's taken months of Rudy's time and he's had to purchase storage for "terabytes" of data because *standing up a new Blacksky "instance", in a total sense, requires literally mirroring everything posted on the network*, including spam and old inaccessible chats on people's https://stream.place streams

[fabrice@fosstodon.org]

@mcc Because if you're banned only by the appview, this seems easy to bypass (just talk to the PDS!), but if you are banned at the PDS level that blocks you from also non-bsky ATProto apps, right? That all look bad to me; my conclusion is that we should own our PDSes (or use a Fediverse style community run one), and that appviews should not exist as centralized services.

[mcc@mastodon.social]

Oh, and let's consider, for a moment, the downsides of an individual user being able to "opt out" of moderation decisions. The problem with misbehavior on social media is force multipliers. One person harassing you is no problem; one person and their 3000 friends is a big problem. Imagine Bluesky and Blacksky ban user X but Trumpsky lets X keep posting. Now their 3000 friends— still in Bluesky's good graces— can see their posts calling to harass you, AND can zero-friction zip over to yell at you

[ratsnakegames@mastodon.social]

@mcc is

is Trumpsky a real thing

[mcc@mastodon.social]

@ratsnakegames No

[ratsnakegames@mastodon.social]

@mcc phew, you had me worried for a second there was another one of Those Bloody Things

[mcc@mastodon.social]

This is why—although, now Blacksky is letting me "see through" Bluesky's worst moderation decisions, I'm glad, because Bluesky's moderation is weird and arbitrary—I think it's a downside of the network, and Mastodon made the right decision not offering this feature. Fediverse defederation forces a degree of soft group consensus on moderation: it's possible to say "if you're talking to X, I don't want to talk to *you*". On Bluesky we are all ghosts walking through walls and this can't be enforced

[operand@todon.nl]

@mcc I guess you could simultaneously see this as a success and a failure for ATproto: decentralization is possible... but you immediately get a lot of the same problems ActivityPub has that ATProto ostensibly solved.