Bluesky is built on an open source ActivityPub alternative called “AT Protocol”. However, Bluesky itself is not open source* and afaik does not yet federate with any other software. The company is a “public benefit corporation”.

From my understanding, Bluesky has good moderation, to the point where Jack Dorsey (the Twitter founder) condemned it and withdrew from the project. That’s a big plus in my book.

• Another commenter pointed out that some parts of it are open source, such as the apps and at least some parts of the backend. Im not sure to what extent the backend is open source.

One is going down the drain first

The latter has been taken over by ElMu and his shenanigans, the former was originally a Twitter-internal project for a decentralised social media interfacing protocol, got forked out from Twitter in 2021 (the year before Musk took over Twitter), has a lot of Ex-Twitter people on it and promises to do a lot of things a lot better than either Twitter (now X) and offer a little more resilience against things like moderator abuse.

Curiously, that last bit is the first time I’ve seen a reasonable use case for Blockchain: Your content can be stored on arbitrary servers and migrated to others. Your identity is tied to keys that can be used to verify your content is actually yours. The info where the public half of the key and all your content are stored is recorded in a public, distributed, append-only ledger, where each entry verifies the integrity of the previous one. Thus, once you’re registered on that, no single moderator can arbitrarily ban you anymore. (Pretty sure there’s a hole in that logic, but I’m not versed enough to confidently assert as much.)

Of course, there’s a caveat: To discover content, you need an index (“relay”) of all the content feeds. That takes some of the content aggregation load off your individual content servers and makes hosting them easier. However, it shifts the content moderation / federation power from the individual instances to the shared index: If a given index blocks your content, people using it won’t see your content.

In theory anyone can host their own relay and everyone can choose which relay they want their content feed to use. In practice, hosting a relay is resource-intensive, bsky have a solid headstart and probably more resources, and their app also obviously uses their own index by default, so if you do want to create a “competitor”/alternative index, you’ll have a lot of catching up to do. They even state that expectation: “In all likelihood, there may be a few large full-network providers” ^src

Which is basically a small-scale version of Google and Bing (and the AT Protocol Overview explicitly uses that comparison): Sure, you can make your own search engine, but if Google is the default everywhere, has a lot of storage and computing power to serve more requests and has way more indexed content, why would people use yours instead? Thus, if you want your content to be seen by many people, you have to play by the big relays’ rules.

Much decentral. Very open.

(I’m being snarky here, but I will give them the benefit of the doubt: They probably do mean to make self-hosting your personal data and content easier, and it’s easier for custom feeds to use single, big relays to draw from rather than doing the indexing and collation themselves. However, it provides them with a lot of leverage and just because they call themselves a “public benefit corporation” doesn’t mean I trust them not to start enshittifying for profit at some point.)