No need for algorithms the people are their own judges, I'm counting on FreeNet to do the crypto for me.
Using Freenet the construction would be very straight forward, Using dynamic content to update all the data would be the beginning.
The front end of the system is like eBay
but the back end is completely dynamic, updated and swirling constantly with each submitted change, once the change is done you will need FreeNet buddies to hack the sent information from your node to a known perimeter of control. That would be like setting up a trap in a local area, but very expensive to setup if people are connecting to public peers.
Now thinking that most people will be honest, it's possible, it will be the wild west in the beginning but there will be paragons of commerce that will arise, they will be who start gaining their deserved share of the pie.
Now creating a system without the need for trust, your going to have to call Satoshi for that, cause I have no clue.
Well thinking about constructing a Trust free system using a goods exchange service would be very intense... that would be a multi-tier system of epic proportions.
It would require Encrypted Geoid locations, UTM coordinates and what not, combined with encrypted shipping services to be dispatched to the location the moment that the item is sold, This would have to be a distributed encrypted shipping service run by Gofors, each one with encrypted ids and encrypted gps systems that guide them to their destination without them knowing the location, the points of interest of the shippers would be to tag the shipments with data matrix barcodes marking it's position in the shipping process, received, in transit, delivered.
Data miners would be employed to calculate the routes that the couriers would require and the most effective route of distribution and pick-up to carry out. This task would be data intensive so would require a multi-pickup aproach by local Gofors so as to limit disclosing the buyer and seller.
Keeping the Gofors safe would require even more encryption on an open network, their locations are known and their vitals are monitored by the Data miners, the information is encrypted as it goes through the network but only the data miner assigned to the Gofor knows their location, if their is a problem they take longer than they should that information is shared with other Data Miners and a concensus reaction is reached, should they ask for an update, how are their vitals? are enforcers required to come in?
Shipping would be run by a distributed system of couriers, both legit and under the table, the miners take care of the route as long as they know the size and dimensions of their load, They take the data from local areas and monitor who is on active duty and dispatch them to do the pick-up for small shipments in a small area multiple couriers may be required and international orders would require risk assesment by the Couriers, do they want to ship the final leg on that international plane with that unknown Gofor acting as passenger?
I'm thinking big, some people may want to carry things for another person if they know the risks, jewellery? a cool little rc toy that is not available in that country? but what if it's drugs? are they willing to take that risk with a package that is undisclosed? that option would have to be given to the Gofors.