That looks like an Iain Banks non-sci-fi book jacket

Both of these services appear to be dependent on BlueSky. I.e., if BlueSky ceased existing, or cut them off from its API, they’d die. In that way, they’re not that different from “Log in with Facebook” or similar.

One could theoretically make one’s own independent AT Protocol network, but not in a way that interoperates with BlueSky as a peer. You’re either a subsidiary part of its network or you don’t exist as far as it’s concerned, which is a much poorer value proposition than ActivityPub and related protocols.

No, because the AT Protocol is not designed for interoperability, but rather for entrenching the silo owned by the main node (BlueSky) whilst giving the illusion of being decentralised. It’s to decentralised social media what Microsoft’s OOXML file format (tl;dr: a memory dump of Microsoft Word’s internal data structures encoded in XML, and useless to anything that’s not Microsoft Word or a very precise emulation thereof) is to open document formats.

The official app appears to be written in React Native and is as laggy and janky as you’d expect. Other than that, more people are using it (and/or interacting with it from elsewhere in the fediverse).

Do friends-only posts only work on the same server, or have they devised a protocol for federating access controls?

No thanks, you keep it.

Let me know when you can have posts visible only to friends (which is not the same thing as “visible only to people who follow you”) and permissions for specific friend lists.

Given how strident the author has been about her views, and that she is still a living person, earning royalties and materially contributing to anti-transgender causes, proclaiming oneself a fan of these books is as least saying that the author’s anti-transgender activism is not a dealbreaker. Making part of one’s identity an aspect of the books’ universe is even more so, to the point where there’s a correlation between people proclaiming their Hogwarts house in their bio and expressing anti-trans views. (TERF/“gender critical” activists having suddenly discovered that they were Slitherpuffs or whatever a few years ago, despite not having expressed any interest in YA fantasy novels before Rowling’s statements, is an observed phenomenon, to the point where such a statement in one’s bio is more likely than not to serve as a feeler for scouting out fellow anti-trans sympathisers.)

Bad example, given that Hogwarts-house-in-bio is a reliable transphobic dog whistle, and transphobia is very much unacceptable in the fediverse.

A place where normies can feel at home, knowing that they won’t feel out of place not having a fursona or favourite Linux distribution and won’t be scolded for not using alt text or some inadvertent picoaggression. Also, the promise of clout.