Bitcoin let us imagine a world without banks.
Now, imagine a world without notaries and without public Records.
Here we are.
Bytestamp (The Internet Timestamp Service) is a timestamp service not based on trust by which can be timestamped any electronic document. It is based on Datacoin, a Bitcoin alternative criptocurrency. The hash of the file, that is unique for each file, is recorded in the Datacoin blockchain and then shared in the miners peer-to-peer network. So, it also go under the Proof of Work. For further explanation, read the FAQ