First of all I would like to mention that the information which you intend to publish in the blockchain for the world to see seems to be incredibly important! xD
In the EOSIO software you actually center the interaction with the blockchain in the following way:
Transactions are pieces of computation that can either run fully to completion or be rolled back or discarded if they are invalid. Each transaction can have one or more actions, so if one of the action fails, the whole transaction fails and none of the other actions are applied on the blockchain.
This model moves away from the concept of transactions being simply a sending of funds from one account to another. Transactions in EOSIO are units of work that happen fully or not at all, similar to classical database transactions. This way, actions become the main place where smart contract work happens, and they can be very flexible. A typical transfer of funds becomes simply a transaction that contains a single action that is applied on the token contract to move the funds from one account to the other. This "transfer" action is defined in the contract's code, and it requires specific parameters, like
to (the accounts), and
amount that is being transferred.
For your case, you could define an action in your smart contract that could be called
publish_important_info with a parameter
info which is the string that gets stored in the blockchain. Your action's code could then grab that info and store it using the EOSIO persistence database API.