iPhone applications provide an unwitting peek at what companies believe is the real purpose of their product. Because of the limited form factor of the iPhone, developers are forced to release cut down versions of apps and what features they choose to include tells a lot about their priorities.

For example, the youtube iPhone app does not even suggest that comments exist wheras it devotes significant space to “similar videos”. Clearly, youtube believes their business success lies in encouraging people to browse through more videos. This is reflected in their benign neglect of the web based commenting system which I think has the potential to be one of the more interesting arenas on the web if it were handled well.

The facebook iPhone app features prominently the ability to take pictures and upload them directly to your profile as well as a well integrated commenting feature. Chat as well is featured heavily in the facebook app. Curiously enough, events are completely missing from the app (although not the web interface) which I regard as a major limitation. Also missing is the ability to forward messages or do anything other than a straight reply. Facebook mail has the potential to become the de facto email replacement but it seems relatively clear that this is an area that Facebook is not super interested in as there have only been a trickle of new functionality related to it’s messaging service.

Google maps allows you to plot a route via car but it doesn’t include the walking or public transit modes that it has on it’s website. Even more annoyingly, it doesn’t have the ability to dynamically change your route to a location as you move around which makes it effectively useless as a GPS navigation system.

Some of these insights would have been obvious without looking at the iPhone app version of websites but I think it does place these distinctions in starker contrast. It doesn’t just have to be the iPhone either, looking at any reduced functionality version of a site can give you a sense of what their developers regarded as essential and optional.