There are many opportunities where you can make money here. Think about an arbitrage service in case of a dispute. Or an escrow service. Or a reputation service

There are many opportunities where you can make money here. Think about an arbitrage service in case of a dispute. Or an escrow service. Or a reputation service maybe? I think that the can be only One marketplace since it relies heavily on the network effect. For OB to be first and biggest is a big deal.