A conceptual model of ATProto and ActivityPub

This article is not a deep technical explanation about how either ActivityPub or ATProto work.

Instead I want to explain how these two protocols have different conceptual models of what an open social network looks like.

Decentralisation means that anyone can set up their own social networking site, and federation means that all these independent sites can connect with each other without a single central authority.

An ATProto app (like Bluesky ) takes the data from all the PDSes in the network.

AppViews aggregate the data, and provide the end-user with a view’ on that data.

Bluesky is a microblogging service that allows you to run your own blog posts.

Anyone can run their own AppView , and build their own product in the ATmosphere.

The ATmosphere is a social graph with 13 million accounts that are free for the taking for any developer to build on top of it.

Bluesky PBC is asking for other organisations and companies to be their competitors so that both companies and companies can contribute to a growing ecosystem.

The challenge is clear: get more people to build products on ATProto .