Simon Willison’s Weblog

Easy explainer: a "blockchain" is a linked list with an append-only restriction, and appending is made incredibly expensive but super parallelizable, so when things work well a big group of people can work together and it's too expensive for a small evil group to compete. [...] Does your problem benefit from storing information in an append-only list, and relying on a central authority to manage it is so bad that it's worth paying the enormous append costs to have a bunch of Chinese servers manage it for you? Then maybe look at a blockchain.

— Tab Atkins