John Rhodes of Webword has just launched the secret project he has working on and enigmatically referring to for the last few months. Trodo is an on-line trading community, where people can hook up and swap books, CDs, DVDs, and other stuff.
Note that it’s swap, not sell. Unlike Ebay, you’re not trying to maximize your profits from the items you list. One book gains you one “credit” for another book. When you sign up, you have to list at least three items you’re willing to trade, and this gives you an initial three credits. With these credits you can then request items from other users.
The economics of this credit system are very interesting. You might think that it would be easily abused. Because each book (or video, or DVD) is worth exactly the same as any other (1 credit), what is there to stop someone from only listing old, decrepit pulp paperback novels, but only requesting shiny new computer books? Well, the credit system itself acts as a brake on this kind of behaviour, because apart from your initial three signup credits, you only get more credits when someone requests one of your items, and you fulfil that request.
If you list nothing but rubbish, no-one will request your items, so you won’t be able to request other people’s “good” stuff. You therefore have an incentive to list items that other will find attractive enough to request from you.
There are many other interesting aspects to the system. Why don’t you hop on over there and take a look?