I spent the day, and will spend tomorrow, at the Peer-to-peer Economics Workshop at UC Berkeley. Most importantly, I'm getting to meet friends such as Bram and Roger, as well as new people such as Tim Moreton and Andrew Twigg, who are taking my stamp-trading ideas forward into new and interesting territory.
I've always been skeptical of economics as an intellectual discipline. It was originally called "the dismal science" because of the pessimism of some of its predictions, but I'm sure the name has stuck because of the quality of the science. Indeed, some of the presentations fit the stereotype perfectly: taking simple questions and muddying them all up with hokey math and fancy sounding theories.
However, the presentation by Hal Varian, was a wonder to behold. In his hands, economics feels much less like a science than an art - an art of explanation. He presented a very simple model of how sharing (including both traditional forms such as libraries and new forms such as P2P networks) affects both the pricing of media works. In fact, it was a dramatically oversimplified model, but that was ok. The simplicity of the model means that it's easy to understand, but it still captures something about the real world. Impressive.
There's good news and bad news on "reputation systems". The good news is that academics are starting to study the topic seriously. The bad news is that the system they're studying is eBay. There's nothing especially wrong with eBay, but I still find it sad to see directions of academic study driven so obviously by commercial popularity.
Regarding trust metrics, it's obvious that a lot of people who should know about them, don't. That's easy to fix, though, and indeed a workshop such as this one is one of the best ways to do so. And, of course, it reminds me that I really need to write up my ideas in academically citable form, for which finishing my thesis will do!