https://jaygraber.medium.com/web3-is-self-certifying-9dad77f...
In the context of TBL's invention combining urls, hypertext, and http, this is about the authentication and authorization steps that ask, "who is making the request, and should they be sent the resource they requested?"
Lacking great peer-to-peer approaches to this, we've gotten certificate authorities and tech giants acting as identity providers. Web3 is about exploring more decentralized approaches here which may, but by no means necessarily, involve blockchains.