This is excellent. I think it's only really missing one thing: curation.
There is an example of moderation: the bizdir business directory. This is really useful, since Dr. Jane Nym is able to find an explicitly trusted contact for Pizza Piano. The problem is that she isn't able to implicitly share either the contact itself (Pizza Piano) or its source of trustworthiness (bizdir) with Ben Bitdiddle. In practice, this forces Ben to fallback on Caller ID, which is precisely the system we intend to replace!
This is the failure of moderation in decentralized networks. Traditional moderation is founded on authoritative hierarchy, which is exactly what decentralization removes from the system. To replace it, we need a decentralized alternative to moderation. I propose curation: each user curates their list of trusted contacts, and publishes it as a list of attestations. The bizdir business directory could actually be a good example of this, so long as we clarify some particulars.
Consider "bizdir" as a participating user of the decentralized network. The bizdir user has published a list of attestations, including the contact for Pizza Piano. There is an opportunity here for Dr. Jane Nym to replicate bizdir's attestation of Pizza Piano, thereby solving the problem for Ben Bitdiddle without requiring his involvement. When Dr. Jane Nym calls Pizza Piano, she is implicitly validating it as a genuine contact. Why not make that explicit? At the end of the call, her petname/contacts app may ask if she trusts the number she just called; or she may have it configured to do so automatically. If she ever finds a reason to distrust the Pizza Piano contact, then she can tell the app to publicly attest her distrust.
So what's the difference here? Isn't bizdir functionally identical, whether presented as a curating user or an authoritative moderator? The difference is that, as a curator, bizdir is explicitly redundant. Ben Bitdiddle doesn't need to interact with bizdir at all. He can benefit from it secondhand via Dr. Jane Nym's redundant "bizdir => Pizza Piano" attestation. On top of that, the validity of Pizza Piano's contact info has been attested to Ben twice, which can only help to drown out any potential outdated or fraudulent Pizza Piano listings. This pattern can feed back into itself, such that Dr. Jane Nym would never have actually relied on bizdir alone as a source of trust, because many of Pizza Piano's customers will have already publicly verified the same attestation.
---
The utility of curation can extend anywhere we expect moderation. The greatest struggle for decentralized social networks is that they are immediately overcrowded by taboo content. Anyone who has been banned from traditional moderated platforms will try to build their home on your decentralized one; after all, one of the core features of decentralization is the circumvention of censorship. The problem is that most of the content that gets banned from centralized platforms is content that the average person is genuinely disinterested in. Just because we want to welcome free speech, doesn't mean we want to spend our time reading hate, watching trauma, or arguing with bullshitters. In order to make a space where regular people willingly participate, we must give users equal power to not participate. We can accomplish this with curation.
Essentially, curation is a shift in strategy. Rather than demanding everyone accept the blatantly false attestation, "this content does not exist" (a moderator ban), we can collectively attest, "this content is garbage", and get back to sharing the rest.