An interesting idea. It reminds me of a barter system, with the similar problem of trying to put together a complex trade which is mutually acceptable. I wonder whether it could be automated if people posted their holdings and what they would accept. Then software could go into this database and try to put together a set of trades that will let someone make a purchase. However it would seem to be very harmful to privacy to have to post all this information. There are some "lightweight payment" schemes out there which have the property that people only accept cash that is "for them". Sometimes there is a broker involved who actually issues the cash on behalf of the merchant (the merchant trusts the broker to do this) so that customers need only go to a smaller number of brokers. Then these systems can be based on heavier payment systems like digicash or credit cards which people use to open accounts with the brokers. I do like the decentralization idea, but these lightweight schemes have some of the same advantages. Hal