[dnomad]

I would say this is a rather limited, technical understanding of a blockchain. The three most interesting aspects of a blockchain are (1) the state of blockchain is visible to all participants (2) the rules (the code) for changing the state is visible to all participants and (3) there is some mechanism to detect and punish rule breakers and aggressors who try to deform the state. Look at it this way and indeed a blockchain is really a very sophisticated collaboration model.

You don't need the distributed consensus or the decentralization or the trustlessness. There are blockchains with central coordinators and without trustlessness that may still prove very useful especially in global finance. People think Bitcoin or Ethereum are complicated but really, they are nothing compared to the global financial system. Distributed blockchain databases are much more elegant than what we have today in terms of achieving consensus on a very large (global) scale.

FedCoin is a crazy idea but it's not stupid. A national public ledger would open a lot of very interesting doors. (Though the republic would likely collapse, see my other comment.) Even if the Fed required only trusted nodes (ie bank-like entities) it still would provide everything from a true national ID system to real, binding peer-2-peer lending between citizens to a system where everybody has perfect, real-time visibility into the national economy (unlike the primitive system we have today where the Fed collects a bunch a data, massages it, and then announces it each month.) Lots of other problems -- everything from medical records to real-estate -- become a lot more tractable.

[Jasper_]

What? There is no mechanism to "detect and punish rule-breakers" in either Ethereum or Bitcoin. Bitcoin's only mechanism is to push global human-readable alerts, or to pressure rule-breakers to stop through a blog post, as in the case of SPV mining: https://bitcoin.org/en/alert/2015-07-04-spv-mining.

If you define "rule-breaker" as "generates invalid blocks", then the only punishment rule-breakers receive is that... their block is invalid, they're ignored, and they get to try again next time.

I don't see any sophisticated collaboration model in play here.

> Even if the Fed required only trusted nodes... Lots of other problems -- everything from medical records to real-estate -- become a lot more tractable.

Why aren't they solved by a database and a public API? What does the blockchain add?

[masterbit]

Blockchain coordinates databases over different legal entities. That's the magic. It's still your DB in your Datacenter when you run your own node. You have autonomy over your own records with your keys. And you have visibility of all other records. A big central DB is under the control of a central body. With a blockchain the central control is / could be limited.

[bitreality]

Definitely, but this is a feature that a centralized authority like the fed would prefer to do without. Whatever technology is behind any sort of "FedCoin" would certainly not be blockchain. They will not relinquish control of their currency, doing so would make themselves obsolete.

[geofft]

(1), (2), and (3) are true of Certificate Transparency.

(1), (2), and (3) are true of a system where a single trusted coordinator gets to order (and perhaps reject) transactions. A slightly less anonymous version of any electronic stock exchange would count.

(1), (2), and (3) are true of the Debian apt repository.

(1), (2), and (3) are true of any game without secret information, like chess or Go or Pretty Pretty Princess.

You could call all of these "blockchains," but I think that makes the term so generic as to be useless. If you want a national public ledger, that sounds interesting, but please call it a national public ledger, not a blockchain.