This is for the “Blockchains are useless unless they’re Bitcoin!!!!” crowd. I give you Nick Szabo:

Recently developed and developing technology, often called “the block chain”, is starting to change this. A block chain computer is a virtual computer, a computer in the cloud, shared across many traditional computers and protected by cryptography and consensus technology…

A block-chain computer, in sharp contrast to a web server, is shared across many such traditional computers controlled by dozens to thousands of people…

Trust-minimized code means you can trust the code without trusting the owners of any particular remote computer… Regardless of where any of the computers or their owners are, the block chain computer they share will execute as reliably and securely as consensus technology allows, up to the aforementioned limits. This is an extremely high level of reliability, and a very high level of security, compared to web server technology.