What are Blockchains?
On traditional server architectures, every application has to set up its own servers that run their own code in isolated silos, making sharing of data hard.
If a single app is compromised or goes offline, many users and other apps are affected.
On a blockchain, anyone can set up a node that replicates the necessary data for all nodes to reach an agreement, and be compensated by users and app developers.
This allows user data to remain private and apps to be decentralized (dapps), as the Internet was intended to work.