What is Storj blockchain?

Storj is a blockchain-enabled data storage network that allows users to access remote, decentralized data storage and retrieval services, or offer storage services by using excess hard drive space and bandwidth. While users' files are not stored on the blockchain, Storj uses hashing, Proof of Work (PoW), key-pair cryptography, and other blockchain features to offer data storage services and rates which are similar to, and in some cases superior to, what is offered by larger centralized cloud storage services.