Where the ISS at was built by Bill Shupp (me). You can read about its motivation in my blog here. But in short, it was built for two reasons. First, the existing ISS tracking/notification tools were decent, but lacking features. So I decided to write the one I wanted to use. Second, I was fascinated at how satellite tracking and predictions worked, so I wanted to learn how to do it.
Feedback is always welcome, feel free to let me know what you think!