<p>With respect to the prior art, in order to improve the efficiency with which products are bought and sold in a marketplace wherein cloud products are bought and sold, this system has: a marketplace page (2) that supplies product information to customers; a sales management system (4) that manages product information that has been registered from the product seller side and manages purchase/contract information from customers; a suitability diagnosis tool that performs a suitability diagnostic process with respect to products and customers; a database that stores data information that includes diagnostic information for diagnosing suitability; a registration means for registering diagnostic information from a product manager in the database; and a means for, as a result of a suitability diagnosis, performing a process whereby suitability diagnosis results information is presented to a customer.</p>
