The first thing to do is identify any potential applications that the new application could interact with. If you're designing for a web page or mobile device, you might want to include applications, technologies, and services from other web pages or mobile devices as well.
Again, I suggest using a whiteboard for the method I describe in this chapter. Write down your target user needs from Figure 8-1. Then build a circle of applications that the web page already offers, as in Figure 8-2.
In this example, I'm assuming that the web page already supports a friends list, photo sharing, status messages, and message handling. I've also placed “Other web services” in the diagram.