Just curious, how is this different from something like a PGP key server?

Better than the eyeball-scanning ghouls.

atproto is currently permissionless world readable, that seems worse to most people (I asked low 100s) than being in a siloed platform with some amount of control over who can see their content

oh, maybe you mean Sam Altman's World with their eye scanning for identity, that is quite dystopian

This might be one of the closest things I've seen to actually being able to own your account - instead of having it not just owned by a second party in every way that matters, but also beholden to a third party via an e-mail or a phone number you can't possibly own in any meaningful way.

That's pretty important in a world where the likes of Google can and will just reject your attempt to log in with a valid password on the grounds of "we don't like you", and force you to "confirm" yourself using a phone number that's defunct since 2009.

The issue is, as often is the case, adoption.

did:web is closer to owning your own identity, this is a central database controlled by an organization

The PLC makes it easy for Bluesky to be a custodian and onboard new users

Sort of.

I like to insist that the PLC Directory collects and distributes updates to highlight how it's different from a database. The latest state of the account is signed by the key that created it, or by a key that succeeded it. The directory can't inject any values, it's just a low-complexity solution for data availability: the "how do I learn about updates" part.

It could decide to hide/reject updates, but then it could just as well be forked and replaced if it did that. If downstream applications decide to get their account updates somewhere else, that's the directory now, without any loss of continuity for the accounts.

You don't get that from a simple database.

One could argue domain registrations, and so did:web, are more of a database controlled by a (large, international) organization than PLC. Plenty of tradeoffs of course.