Every action on this website generates a signed transaction that is broadcast on a P2P network. This is just a light client like blockchain.info.
The magic is that you don't realize it is a blockchain, yet under the hood it is. Anyone can run a full node on their local machine and have access to all content.
Alot of newcomers will be flocking soon, maybe we need a intro to the blockchain page on steemit as most people will have never even heard of bitcoin let alone blockchains and steemit. But this will spread like a wild fire.