An anonymous reader writes: If digital currencies are fundamentally different than physical ones, why do they work in the same way? That's a question being asked by Couchbase co-founder J. Chris Anderson, who's building a currency and transaction system where reputation is the fundamental unit of value. "Unlike with bitcoin—which keeps its currency scarce by rewarding it only to those who participate in what amounts to a race to solve complex cryptographic puzzles—anyone will be able to create a new Document Coin anytime they want. The value of each coin will be completely subjective, depending on who creates the coin and why. 'For example, the coin my disco singer friend created and gave me at my barbeque might be what gets me past the rope at the club,' Anderson says. A coin minted by tech pundit Tim O'Reilly might be highly prized in Silicon Valley circles, but of little interest to musicians. 'It's a bit like a combination of a social network with baseball trading.'" Anderson isn't aiming to supplant Bitcoin, or even challenge the money-exchange model that drives society. But he's hoping it will change the way people think about currency, and open up new possibilities for how we interact with each other.