This is a great introduction to the IPFS protocol!
The Interplanetary File System technology is centered around a distributed hash table (DHT), Merkle-Tree DAG data structure, and BitTorrent to create a decentralized, permenant web protocol.
HTTP is slow, centralized, and impermanent. IPFS is a solution.
Since IPFS relies on a decentralized storage system for hosting content, Filecoin was introduced as a blockchain-based currency to incentivize participation and storage.
Learn more from Siraj:
Or checkout the white paper at https://ipfs.io