It is a protocol and a P2P network for storing and sharing data.
Initially released in 2/2015
It is a decentralized system. Each user-operator holds a portion of the overall data.
Any user in the network can serve a file by its content address, and other peers in the network can find and request that content from any node who has it using a distributed hash table.
Created by Juan Benet. Founded Protocol Labs in 5/2014