What we want to achieve is loose coupling on commodity platforms. This provides scalability and is also best for costs, so the result is the best price/ performance. Loose coupling combines queuing, to remove time dependencies with use of a non-application-specific data format to remove data dependencies. Figure 11.2 illustrates loosely coupled systems. A consumer is interacting with an ecommerce system. The ecommerce system has copies of elements of the product catalog and customer data. When a purchase is made, a message is sent to the ERP system for fulfillment. This system may, in turn, send a message to a business partner. These messages may be asynchronous, so that the customer interaction does not wait on the response from the back end.