I haven't seen any examples yet. Proposed uses of a blockchain tend to fall into one of the following two traps: 1) The problem domain doesn't need decentraliz

I haven't seen any examples yet. Proposed uses of a blockchain tend to fall into one of the following two traps: 1) The problem domain doesn't need decentralization. If there is a trusted central authority then a cryptographically signed git database suffices. 2) There is no economic incentive for mining. With Bitcoin, there is an incentive for miners to spend significant amounts of electricity and computational power competing to add blocks to the blockchain, since they are rewarded with newly minted coins and transaction fees. The security of the whole network depends on this being a very expensive process because the more costly it is to add a new block to the ed of the chain, the more costly it will be for a malicious adversary to construct an alternate blockchain history (to perform double spend attacks and more). Non-currency blockchain solutions can't award in-chain rewards to the miners so an offchain inentive must be found (which is extra tricky if you follow rule 1 and assume that the network participants do not trust each other)