The bitcoin digital currency is driven by open source software that runs across thousands of machines around the globe. Borrowing code from this rather clever piece of software, independent hackers have already built applications such as the Twitter-style social network Twister, the encrypted e-mail alternative Bitmessage, and the unseizable domain name system Namecoin. But Buterin believes that many other applications can benefit from the genius of the bitcoin software, and that’s why he’s joining forces with several other hackers to create something called Ethereum.