Here is an excerpt from the offical docs for the curious:
"Why not use ActivityPub?
ActivityPub is a federated social networking technology popularized by Mastodon.
Account portability is a major reason why we chose to build a separate protocol. We consider portability to be crucial because it protects users from sudden bans, server shutdowns, and policy disagreements. Our solution for portability requires both signed data repositories and DIDs, neither of which are easy to retrofit into ActivityPub. The migration tools for ActivityPub are comparatively limited; they require the original server to provide a redirect and cannot migrate the user's previous data.
Another major reason is scalability. ActivityPub depends heavily on delivering messages between a wide network of small-to-medium sized nodes, which can cause individual nodes to be flooded with traffic and generally struggles to provide global views of activity. The AT Protocol uses aggregating applications to merge activity from the users' hosts, reducing the overall traffic and dramatically reducing the load on individual hosts.
Other smaller differences include: a different viewpoint about how schemas should be handled, a preference for domain usernames over AP's double-@ email usernames, and the goal of having large scale search and algorithmic feeds."
a very opinionated piece that leads by conclusion rather than building up to it.
The main part of ATProto that is centralized is the PLC and that will eventually be made (most likely) into a consortium. PDS hosting is debatable
That being said, it should be possible to run completely independent atproto networks today. We have several dev infra setups for doing it in the ecosystem
Anything "social" basically - the first ideas that come to people's minds are of course things like: GitHub but on ATProto, Instagram on ATProto, Tiktok on ATProto, Reddit on ATProto…
I don't think that Matrix chat was used much after the initial months, I've only really heard about it in legends... That Discord (the ATProto Touchers) is community-run.
ATProto is a lot of fun to work with, but of course by no means perfect. The biggest challenge right now is dealing with private data, I hope they can figure out a way to support it soon.
> unicode scalars, which most languages index strings in
Very few do. Of moderately popular languages, Python is the only one I can think of. Well, Python strings are actually sequences of code points rather than scalars, which is a huge mistake, but provided your strings came from valid Unicode that doesn’t matter.
Languages like Rust and Swift make it fairly easy to access your string by UTF-8 or by scalar.
Languages like Java and JavaScript index by UTF-16 code unit and make anything else at least moderately painful.
> This is somewhat of an unfortunate tech debt thing as I understand, and it was made this way mostly because of JavaScript, which doesn’t work with UTF-8 natively. But this means you need to be extra careful with the indexes in most languages.
I’m confused here. You established indexing is by UTF-8 code unit, then said it’s because of JavaScript which… doesn’t do UTF-8 so well? If it were indexed by UTF-16 code unit, I’d agree, that’s bad tech debt; but that’s not the case here.
Bluesky made the decision to go all in on UTF-8 here <https://docs.bsky.app/docs/advanced-guides/post-richtext#tex...>—after all, the strings are being stored and transferred in UTF-8, and UTF-8 is increasingly the tool of choice, and UTF-16 is increasingly reviled, almost nothing new has chosen it for twenty years, and nothing major has chosen it for ten years, it’s all strictly legacy. Hugely popular legacy, sure, but legacy.
Hmm… Yeah, I guess each language does it kinda differently. At least Ruby also does it similarly like Python.
> I’m confused here. You established indexing is by UTF-8 code unit, then said it’s because of JavaScript which… doesn’t do UTF-8 so well?
It's not that UTF-8 is because of JavaScript, it's that indexing by bytes instead of UTF-8 code units is because of JavaScript. To use UTF-8 in JavaScript, you can use TextEncoder/TextDecoder, which return the string as a Uint8Array, which is indexed by bytes.
So if you have a string "Cześć, #Bluesky!" and you want to mark the "#Bluesky" part with a hashtag link facet, the index range is 9...17 (bytes), and not 7...15 (scalars).
When the encoding is UTF-8 (which it is here), the code unit is the byte.
They called the fields byteStart and byteEnd, but a more technically precise (no more or less accurate, but more precise) labels would be utf8CodeUnitStart and utf8CodeUnitEnd.
Been pondering for my team to use it for our product’s timeline. I don’t particularly want our user base to be Bluesky, but it’d be good to have support for the protocol, and control over the system.
Have there been any products go embraced this? Or is it like ActivityPub where basically the whole thing is Mastodon.
This isn’t quite true. WordPress.com announced they were planning on ActivityPub support, but that is a separate entity run by a commercial company (Automattic).
Their plan was to support it specifically on Tumblr, as well as helping fund an open source plugin for it; there have been no plans to integrate it into the WordPress software directly.
I believe they’ve also deprioritised it as they did significant layoffs recently.
Beyond Bluesky, there's a growing ecosystem including Pebble (a self-hosted PDS), Skychat (messaging), Skeet (app framework), Graysky (mobile client), and several specialized feeds/algorithms - unlike ActivityPub, ATProto's architecture allows for more diverse application types while maintaining interoperability.
For now mostly just small things that the Bluesky dev/user community is playing with, but check out e.g. Tangled which is meant to be a GitHub alternative on ATProto: https://tangled.sh
Readit News
"Why not use ActivityPub?
ActivityPub is a federated social networking technology popularized by Mastodon.
Account portability is a major reason why we chose to build a separate protocol. We consider portability to be crucial because it protects users from sudden bans, server shutdowns, and policy disagreements. Our solution for portability requires both signed data repositories and DIDs, neither of which are easy to retrofit into ActivityPub. The migration tools for ActivityPub are comparatively limited; they require the original server to provide a redirect and cannot migrate the user's previous data.
Another major reason is scalability. ActivityPub depends heavily on delivering messages between a wide network of small-to-medium sized nodes, which can cause individual nodes to be flooded with traffic and generally struggles to provide global views of activity. The AT Protocol uses aggregating applications to merge activity from the users' hosts, reducing the overall traffic and dramatically reducing the load on individual hosts.
Other smaller differences include: a different viewpoint about how schemas should be handled, a preference for domain usernames over AP's double-@ email usernames, and the goal of having large scale search and algorithmic feeds."
The main part of ATProto that is centralized is the PLC and that will eventually be made (most likely) into a consortium. PDS hosting is debatable
That being said, it should be possible to run completely independent atproto networks today. We have several dev infra setups for doing it in the ecosystem
https://discord.atprotocol.dev/
Of course the spec is good too, very easy read
https://atproto.com
https://docs.bsky.app
One of the most interesting projects is tangled.sh - a github-like using atproto for the social layer, which fits perfectly.
Bluesky's name collision was pretty avoidable here but I guess they thought the obvious name was BS.
. . .
ATH
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Very few do. Of moderately popular languages, Python is the only one I can think of. Well, Python strings are actually sequences of code points rather than scalars, which is a huge mistake, but provided your strings came from valid Unicode that doesn’t matter.
Languages like Rust and Swift make it fairly easy to access your string by UTF-8 or by scalar.
Languages like Java and JavaScript index by UTF-16 code unit and make anything else at least moderately painful.
> This is somewhat of an unfortunate tech debt thing as I understand, and it was made this way mostly because of JavaScript, which doesn’t work with UTF-8 natively. But this means you need to be extra careful with the indexes in most languages.
I’m confused here. You established indexing is by UTF-8 code unit, then said it’s because of JavaScript which… doesn’t do UTF-8 so well? If it were indexed by UTF-16 code unit, I’d agree, that’s bad tech debt; but that’s not the case here.
Bluesky made the decision to go all in on UTF-8 here <https://docs.bsky.app/docs/advanced-guides/post-richtext#tex...>—after all, the strings are being stored and transferred in UTF-8, and UTF-8 is increasingly the tool of choice, and UTF-16 is increasingly reviled, almost nothing new has chosen it for twenty years, and nothing major has chosen it for ten years, it’s all strictly legacy. Hugely popular legacy, sure, but legacy.
> I’m confused here. You established indexing is by UTF-8 code unit, then said it’s because of JavaScript which… doesn’t do UTF-8 so well?
It's not that UTF-8 is because of JavaScript, it's that indexing by bytes instead of UTF-8 code units is because of JavaScript. To use UTF-8 in JavaScript, you can use TextEncoder/TextDecoder, which return the string as a Uint8Array, which is indexed by bytes.
So if you have a string "Cześć, #Bluesky!" and you want to mark the "#Bluesky" part with a hashtag link facet, the index range is 9...17 (bytes), and not 7...15 (scalars).
When the encoding is UTF-8 (which it is here), the code unit is the byte.
They called the fields byteStart and byteEnd, but a more technically precise (no more or less accurate, but more precise) labels would be utf8CodeUnitStart and utf8CodeUnitEnd.
Those old enough will know :)
Have there been any products go embraced this? Or is it like ActivityPub where basically the whole thing is Mastodon.
This isn’t quite true. WordPress.com announced they were planning on ActivityPub support, but that is a separate entity run by a commercial company (Automattic).
Their plan was to support it specifically on Tumblr, as well as helping fund an open source plugin for it; there have been no plans to integrate it into the WordPress software directly.
I believe they’ve also deprioritised it as they did significant layoffs recently.
I would also discard services that auto post to the fediverse but are not actively used by the majority of users as such.
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