In recent years, firms seeking to simplify the process of selling their products to busy customers have been turning to online apps, or Web-based application programs. One increasingly useful type of app for many small businesses is the quick-response (QR) app. Middlemen companies, such as Kaywa AT and Scanbuy, Inc, offer these apps.

The apps enable sellers to create codes they can place on poster ads. Consumers can scan the ads with their smartphones to place orders for the firm's products. For instance, an individual who is about to board a commuter train can use a smartphone to scan a code from the ad of a coffee shop near the train's destination. The code enables the smartphone to acquire the QR app, which in turn displays the coffee shop's menu, from which the individual can choose items to purchase remotely. The individual can then pick up those items at the coffee shop upon arrivalhence completing a mobile purchase made possible by a middlemen company that offers the QR app linking the individual to the coffee shop.

Why do you suppose that firms such as coffee shops are willing to pay fees to middlemen for ad codes to be used with QR apps?