Distributed Autonomous Corporations (DACs) are a generalization of the concept of a crypto-currency where the currency is backed by the services its miners perform rather than a real-world commodity like gold, oil, or, ahem, thin air. If we can barter for goods and services, why can’t we back currencies with goods or services? DACs may be simultaneously viewed as crypto-currencies and unmanned businesses. As businesses, they perform services intended to be valuable to their customers. Such services might include money transmission (Bitcoin), asset trading (BitShares), domain name services (DomainShares), or a thousand other business models sure to emerge as people realize that DACs are not mere “altcoins”.
http://invictus-innovations.com/i-dac/