A cool iPhone/iOS feature is an SDK’s ability to ‘bind’ itself to a custom URL scheme and for that scheme to be used to launch the application from either a browser or another application. This can also be referred to as in-app ‘deep-linking’, which consists of using an uniform resource identifier (URI, a string of characters used to identify a name of a web source) that links to a specific location within a mobile app vs. simply launching the app. For example, you might want to deep link a user from your app directly to a certain Facebook page vs. having that user link straight to Facebook’s homepage.
To see how this works, type fb://profile/33138223345 into your phone’s browser (if you have Facebook installed, that is). This should not only launch your app, but take you straight to wikipedia’s Facebook page within the app.