But if you're not signing any black- or grey-hat documents or transactions, then you can just pick a trustworthy central party to receive the hashes and publish the chain.
The startup GuardTime has been doing document timestamping and integrity checks with a blockchain for a bit while longer than bitcoin.
* You hash documents that you want to timestamp, and send the hash to them.
* They hash all received hashes and the previous head of the blockchain together, and publish the head hash in the paper copy of Financial Times: https://guardtime.com/photos/ft14-2.png
* The exact contents and "created before than" timestamp of the documents can now be fully verified, unless someone can manage to gather and destroy all paper copies of Financial Times published after it was sent to them.
The incentive for them is an usual freemium payment model.