Although I'm sure it has arisen independently several times, my introduction to the concept of a Reputation Economy came to me from Cory Doctorow's debut novel "Down and out in the Magic Kingdom" and the concept of "Whuffie" used by the fictional utopian society for the few things that were still scarce in a world of free energy, perfect biology and "replicators"... The best seats for a show, first puff of a joint, the attention of a talented professional, the apartment with the nicest view... whatever someone wants that someone else also wants is by definition scarce, after all.
So... for those who haven't read the book and don't care to Wiki the subject, Whuffie is a lot like "likes" or "+1s" on various Social Media. It's all sliced and diced and weighted a certain way in the books but it was more about the concept than the details IMHO. If an issue ever comes up where only one person can have something then (all else being equal) the person with the high Whuffie score gets it.
We don't have replicators or free energy, 3D printers and solar panels are neat and all but we're not ready for the Vulcans (or even The Culture!) quite yet, but we do have a Digital Economy emerging alongside an Industrial Economy in decline and the realm of the Digital is inherently Post-Scarcity in most ways that matter.
What I am interested in is the use of the software and concepts behind Cryptocurrency projects like Bitcoin and Peercoin to establish useful metrics like Trustworthiness, Quality of Product, Quality of Service and others within the Digital Economy. I have some ideas but nothing really solid and coherent, and even less idea about how such a system would interface with the still relevant "Meatspace" Economy.
Any thoughts would be appreciated, as would directions towards any existing projects along these lines that may already be underway.