There was a HN Launch discussion recently that might be relevant here: https://news.ycombinator.com/item?id=20413420
The decentralization comes from (a) open-source GPLv3 code, (b) permissionless blockchain, (c) enabling users to host private data lockers, among other things.
The discussion on decentralization in our recent SEC offering circular -- page 49 and page 69 at https://stackstoken.com/circular -- is also relevant here.
"At some point when this decentralization process is complete and there is a healthy ecosystem of applications and users on the network, Blockstack PBC expects to develop new business models"
This is the Field of Dreams approach to reinventing the internet economy.
Also from that circular: "core nodes are hosted on Microsoft Azure, Google Cloud, and Amazon Web Services, or AWS, which provides us with computing and storage capacity. Some elements of this complex system are operated by third parties that Blockstack does not control and that could require significant time to replace. We expect this dependence on third parties to continue"
I'm struggling to understand what is decentralized about any of this. From my vantage point, you got VC to pay you to run a project on the cloud by saying "blockchain" a lot.
The protocols under the hood ensure that each user chooses where their data gets stored -- all that's required is that wherever it is, it's available via HTTP(s) so it can be loaded into your Web browser. As such, Blockstack-powered applications hold no user state -- the user takes their data with them, and "brings their own storage" to the application. The blockchain component acts as a discovery mechanism, whereby any user can discovery any other user's public keys and storage locations, given a username.
Blockstack PBC gives users a small amount of free storage space to help onboard them, and runs some publicly-routable Blockstack nodes. However, nothing stops you from electing to store your data in your own storage provider (e.g. S3, Dropbox, your personal server, etc.).