This makes the process much simpler. For example, imagine how difficult and time consuming it would be to find a business that is willing to trade you printing services for the services you have available. The exchange does this for you. All you have to do is call them and tell them your business needs and what services or products you have available to barter. The exchange keeps a database of all of its clients.
Most exchanges limit the number of members that can offer a service.
For example, it is not feasible for 10 dentists to join. This would create more supply than demand. The exchange will set up an account for each member. An initial membership fee is usually charged by the exchange. In addition to the one time membership fee, the exchange charges a commission on each transition.