It's a very long post, but a lot of it is a detailed discussion of terminology in the appendix -- no need to read that unless you're into definitional struggles.
Kuba's link i that thread is good, it looks like there's currently about 370 PDS's -- Bridgy Fed got an exception from Bluesky so is the only one that currently has more than 10 uses. https://blue.mackuba.eu/directory/pdses I know some people who just run the open-source code for Bluesky's PDS (which is pretty straightforward) and some run other implementations.
Blueksy's approach to decentralization is very different from ActivityPub but it's definitely decentralized. (Also that article's over a year old, and some things have changed since then.). But, like I say in the article, not everybody is so welcoming!
They're still cosplaying decentralisation. Google hosts images on a separate domain to the one where they serve documents, are they decentralised? When we see more indexers, by all means let's consider BlueSky decentralised, but until then, they're just offloading traffic.
I hope they start supporting people who want to run an indexer. Right now they just point to their source code and say, "if you can get this largely undocumented complex service running on your own, you can run a indexer, but don't ask us for any help".
I'm not entirely confident that it will happen before their only funding source decides to cut off the cash flow.
@thenexusofprivacy to me, as long as bluesky can’t properly communicate and federate with any social network (activitypub apps included) we can’t define it as fediversed but I’m curious to have your opinion
Personally I think that the connectivity via Bridgy Fed and Friendica are strong enough that it makes sense to consider Bluesky an instance on the ActivityPub Fediverse. Threads currently has less connectivity, and people in general consider it part of the Fediverse. For what it's worth, in a discussion on Social Hub, Evan Prodromou also said he saw Bluesky as an instance in the ActivityPub Fediverse.
I also think that the ATmosphere is fediverse (descentralized social network) in its own right. So is Bluesky, as well as being part of the AcivityPub Fediverse and the ATmosphere.
@thenexusofprivacy so if I follow your pattern, we can also consider twitter as an instance of the activitypub fediverse as some accounts are crossposting/mirroring their twitter acccount on mastodon (as such as @_formula1_) ?