Bitmessage is also pretty awesome already...
But I guess as long as that data is centralized it could be censored.
In essence, only valid queries would be transmitted and replicated across peers.
It would not be a single ledger, it would be a collection of ledgers. Data that is often queried would have higher short term redundancy, that would face over time. Any data submitted would be have at least 10 or 25 copies across all clients, and data would be found through a DHT.
I guess public data would be encouraged since visible by everyone, but private encrypted data be limited. Trust and data moderation are also problems.