Many designers don't look at how consumers will use the apps or where they are when they use them. This article basically tells the designer to step back from the phone/design and put yourself in the users shoes. Think how they would think and design around that.
Designing an iPhone App can be a lot of fun, but it's also a lot of hard work. Research is key when designing a app because you're not designing for one person or one client, you're designing for a numerous amount of people with all different life styles. And being able to cater to their needs through your app isn't an easy task. If you do your research and execute successfully, you'll be raking in the dough!
I would definitely recommend this site/article to anyone beginning in the field of designing phone apps.