Love this.

The post mentions using the blockchain for unique username registration and mapping to public key hashes, and as it turns out there's a project I and others have been working on that does exactly this called Blockstore.

Here's the link if anyone wants to check it out: https://github.com/namesystem/blockstore

The way it works is there's a mapping between a unique name and a hash in the blockchain, and then there's a mapping in a DHT from the hash to the data to be associated (which can be a plain old public key and can also be a JSON file that references a public key and other identity information).