Using a proof of work to build a distributed ledger of transactions - whether it be of money or messages or anything else - was an original innovation of BitCoin, inspired by Nick Szabo's earlier work. Proof of work was used in hash cash, but not in a peer to peer network. My comments regarding political views were more a response to the article.
Good point. I think we're actually on the same page, but with different thoughts on how to classify the "breakthrough".
I consider the technological breakthrough to be hash cash. It couldn't have been possible in a P2P network without the economic incentives reaped from Bitcoin mining.
The analogies to Uber and AirBnB are actually pretty strong here. The tech that brought them to bear was the internet/mobile, but the payment/reputation structure is what made the P2P network possible.
Thinking about this more, it's definitely not a breakthrough to use a consensus algorithm to maintain a set of transactions over a distributed system (such as a P2P network). This has been done many, many times.
The only difference is that Bitcoin literally pays the nodes to act nicely.
