[bachback]

Anyone interested should study the script system and Namecoin.

"Restricting transactions to such a simple form would restrict Bitcoin to exactly the possibilities traditional currencies had (though decentralized). However, Satoshi saw the potential to allow it to do more, and introduced a script system. He wasn't around anymore to bring it to practice, but Mike Hearn wrote down some of the things Satoshi had in mind on the Contracts page of the Bitcoin wiki."