MicrosoftNicholas Theile ION is a Decentralized Identifier-centric protocol (https://w3c-ccg.github.io/did-spec/) tuned for scale, and is quite a bit different under the hood because of a few key assumptions: 1) IDs are not friendly names, 2) IDs are non-transferable, 3) global state is strongly eventually consistent. These are reflected in the protocol's rules that unlock a few key attributes we desired in an open protocol. Blockstack's Gaia Hub was loosely based on a concept we developed in the OSS community many years ago that is in the longer standards track of development under DIF, called Identity Hubs: https://github.com/decentralized-identity/identity-hub/blob/master/explainer.md - you'll notice their concept of Collections semantic storage is the same, which was something they adopted from the wider community in DIF. (aside: I have actually been working on many of these components in one way or another since ~2011 at Mozilla, prior to joining MSFT)
In terms of why people pin batches you are included in via IPFS: turns out Identity/PKI is quite valuable, and maintaining the full node global state is basically a rounding error for millions of businesses and entities. Entities already maintain this sort of data today for free, so we believe they will continue to do so. You can also persist your own PKI metadata without the need to rely on anyone, which is a great feature of the protocol that empowers users to exist in the decentralized identity ecosystem without any aid from companies.
