This is a big milestone for Bluesky!
We've had the federation sandbox running for over six months but we're now able to commit to open federation on the production network this month as well. There's also stackable moderation coming shortly, which enables other individuals/orgs to operate moderation labeling services that users can choose to use.
The technical challenges of setting up an (efficiently) scalable decentralized social network were quite interesting. The infrastructure itself is quite decentralized, with standalone PDS instances and two small shared-nothing datacenter PoPs. We're using SQLite with millions of individual databases for each user's repository and ScyllaDB for the global indexing service (AppView).
https://bsky.social/about/blog/5-5-2023-federation-architect...
If anyone has questions, technical or otherwise, some of the team should be around today to answer them.
Edit: HN'ers might also appreciate this paper written primarily by Martin Kleppman about Bluesky and AT Protocol
https://arxiv.org/pdf/2402.03239.pdf