Silkcoin,

The registration mechanism you're proposing has an interesting application towards preexisting non-p2p systems.

Suppose a website owner who employs a home grown authentication system is able to add a Silk authentication module allowing his system to verify the identity and authenticate visitors against the blockchain. The process could be made seamless for the user via browser plug-in for challenge/response authentication, or token based a la OAuth. The website owner would never need to store the users credentials.

I believe what you're proposing, in particular, decentralized content could coexist and benefit preexisting non-p2p systems.

I'm doing some work in this area, have been hacking on Bitcoin's P2P protocol. Ping me if anyone wants to discuss further, hopefully outside the fray of the ANN thread!