Sia is an actively developed decentralized storage platform. Users all over the world contribute disk storage from their computers to form a decentralized network.
Anybody with siacoins can rent storage from hosts on Sia. This is accomplish via "smart" storage contracts stored on the Sia blockchain. The smart contract provides a payment to the host only after the host has kept the file for a given amount of time. If the host loses the file, the host does not get paid.
(Note one of its splendid features - erasure coding - a near future must for the big data.)