The beauty of a blockchain smart contract is that it enables an authenticated permanent record of a transfer of value. That value can be your personal data or your home or currency - anything you determine has value and someone else agrees to exchange with you. In the era before block chain and ubiquitous search, a broker would match those seeking to perform an exchange with those who had the "goods." The broker would also provide some assurance of trustworthiness. These days, ubiquitous search displaces the "introduction" the broker used to. The smart contract sets terms for and enables the exchange. The block chain is the record of the exchange. Everything anyone wants to exchange is now easily converted into a market.
The anonymity of the transaction due to encrypted keys protecting the identity of both parties to a contract has terrific appeal for those of us who value our autonomy and privacy. We know that the other guy may be getting away with not paying his taxes.... and use of a smart contract on the blockchain gives us the same potential to avoid full participation in the social contract that corporations or wealthy individuals who find tax dodges and tax havens have available. However, our very anonymity leads to a competition to discover who is cheating (Wikileaks) or to cheat better than the next guy (Silkroad). It generates the opposite of a cycle of escalating virtue. We hide from one another and try to catch each other. I would suggest that is a social drain; a depletion of our productive energy.
We are confronted with a real dilemma. What takes precedence - the social contract or privacy? Boundaries between people and nations are more permeable than they have ever been. ISIS knows this. We too know it instinctively. Allow me to argue for required layers of transparency in smart contracts - where the parties to the exchange and the "goods" exchanged are part of the public record, and are auditable and therefore taxable. Taxes are a necessity for developing our infrastructure and educating our kids and providing services. Smart contracts that enforce trust between the parties to an exchange have to include that third party, the communities we are members of.
Let's formulate a chain of smart contracts that hold each of us accountable at a social level - and that protect what can be and should remain private.