Devs running their own PDS hosts are still unable to federate on the production network, for the time being. The dev sandbox will of course remain online indefinitely. The major scaling push continues, but things are progressing rapidly!

I had a lot of issues with timeouts and error codes when loading a thread and replying to it this morning. Would that be a cross-PDS operation?

There actually isn't any cross-PDS communication (the app only talks to your PDS directly) but there could still be some (hopefully minor) issues so we'll look into it. Thanks for the report!

I also just got this when trying to load a feed

We're checking the logs for what the earlier issues may have been. The For You feed will hopefully resolve itself, it's likely caused by some caching on their side that they can hopefully improve. It may resolve itself (once the cache is updated).

Aren't the feeds the instances themselves?

One way to think of it: Feeds are "Algorithmic Federation" (anyone can run a server that provides a custom feed) PDS hosts are "Data Federation" (anyone can run a server that hosts accounts with their posts/likes/etc)