I think it’s reasonable to assume that when OP asked about “joining” each platform, they wanted to use each platform natively.
No. For each Mastodon, Lemmy, or Peertube server you want to join, you need a separate account on the server.
I don’t know what the point of the gif is, so I’m not going to respond to it.
Is Matrix federated? That’s also centralized
There's way more to Wafrn than that, and it's extremely interesting.
You can treat Wafrn like an independent ATProto platform (like Blacksky). It has its own PDS and AppView (which uses Blacksky's Relay), so it's not at all dependent on Bluesky for obtaining posts (assuming those posts are also published on an independent PDS).
What's unique is that Wafrn is actually ActivityPub-first, meaning it doesn't have any issue interacting with Mastodon users, but doesn't have all the same features of a normal ATProto platform. For example must have your account on Wafrn in order to use it (as opposed to blacksky.community, which lets you sign in with an existing account on another ATProto platform); you can, however, sign into bsky.app (or blacksky) with an account created on Wafrn.
Could people in states blocked by the main network use it through these?
Yes, and they wouldn't even need to migrate their accounts to do so (although they probably should).
Fediverse Reports regularly talks about updates with ATProto, and I found this blog post mentioned in another blog post from WeDistribute.
The most interesting development as of late is the progress of Blacksky. It is the first major attempt at creating an independent "Bluesky Instance"–where in that it's functionally the same as Bluesky but doesn't rely on any of Bluesky's infrastructure.
There is also Wafrn, which is really hard to explain. @[email protected] is in this thread somewhere and will have to explain it.
ideally they would close signups and suggest people signup on alternatives instead
Is that what you would actually expect Bluesky to do if they were committed to decentralization?
Why is there a picture of Chappell Roan?
I'd like to see what the metrics for the Fediverse would look like if it included federated Threads users.
I'm just going to respond to what you said before you edited your comment to be a reaction gif.
Since (as of November of last year) a majority of Bluesky's user base is non-technical, they have don't have the knowledge or motivation to switch to another PDS. If 30 million users joined mastodon.social, the fediverse would also be centralized.
The only way for Bluesky to be decentralized by the metrics you use is for them to force users onto other PDSes.
That is by design. From a user’s perspective, the only indication that Bluesky is ~~decentralized~~ federated is the option to select a different “hosting provider” when logging in.