We find inventive ways to commit to transactions without using the blockchain, essentially “caching” them until an appropriate time to actually engage in final settlement on-chain.

The Lightning Network is the first and most mature example of a system designed to accomplish this reconciliation in a decentralized fashion.

Lightning has not exactly evolved as we hoped it would — a pure end-user payments network — but it has undeniably demonstrated itself as the first viable second-layer scaling solution for Bitcoin. It might wind up becoming more of an aggregate settlement layer, or a network more suitable for businesses and services than end users (though not impossible for them to use), but it is so far a resounding success.