Filecoin is a decentralized storage network, constructed over blockchain technology. It allows users to "rent" unused hard drive space. The blockchain uses both proof-of-replication and proof-of-spacetime. The transactions within the network are made with the crypto token FIL.
The main difference with the traditional cloud storage is that Filecoin is decentralized. The information is thus, more protected and not censorable s it could be done by the owner of a cloud server. The information is also more easy to retrieve. Filecoin rewards the network nodes that store data on their blockchain network with FIL.
Proof of space-time (PoST) is a proof that shows that time has been spent keeping the reserved space unchanged. Proof-of-replication (PoRep) is a proof that publicly verifies a claim that the node is dedicating unique resources to store one or several retrievable replicas of data. Once the proofs are confirmed the rewards are received in FIL.