They are building a distributed file store system. They use consensus algorithms to ensure data integrity. There is a specification for a crypto-currency on top of that.
I do not believe the consensus algorithm has been fully implemented, but what they have looks promising.
The documentation is not great, but here is a link to more technical detail about how data is stored in the system:
https://github.com/maidsafe/MaidSafe-Vault/wiki/Documentatio...
(Of course there were consensus protocols already in distributed systems research, but generally they've relied on having a known set of nodes.)