Imagine that we have a huge trading and logistics company. There are tens of thousands of different products on the shelves; hundreds of lorries come to our warehouse bringing new goods, and hundreds of lorries deliver goods to our customers. To manage the information, we have an inventory system that keeps track of the goods every day, hour, and minute to know what we actually have in the warehouse. We serve our customers without humans managing the warehouse information. Formerly, there were phones, fax machines, and even telex, but today, all we use is the Internet and web services. We do not provide a website for our customers. We have never directly served the end users in our imagined business, but these days, we have a subsidiary that we started off as a separate company to do just that. They have a website, and it is totally independent from us. They are just one of our hundreds of registered partners who each use a web service interface to see the products we have, order products, and track the order status.