Storj is a crypto currency built on Storj DCS(decentralized cloud storage), which is used for storage of data in a decentralized manner. Storj gets its storage space from farmers, farmers are people who give their hard drives or storage space to Storj to use in return for Storj coin. So when someone gives Storj some data to store it encrypts that data and breaks it down to many pieces (this is called sharding) and then these shards are stored on the farmers storage space. If someone wants to retrieve their data, the shards are retrieved and combined before the data gets downloaded. The benefit of using Storj is, that the storage of the data is decentralized and way more safer since there is no third party involved and it is managed by the Storj community.