Pretty good little blog post. 
http://daringfireball.net/2009/04/complex
"The iPhone was not conceived merely as a single device or a one-time creation. It’s a platform. A framework engineered for the long-run. The iPhone didn’t and doesn’t need MMS or a better camera or a video camera or more storage or cut/copy/paste or GPS mapping or note syncing, because the framework was in place so that Apple could add these things, and much more, later — either through software updates or through new hardware designs. The way to build a complex device with all the features you want is not to start by trying to build a device with all those features, but rather to start with the fundamentals, and then iterate and evolve."
...click the link for the whole article.
http://daringfireball.net/2009/04/complex
"The iPhone was not conceived merely as a single device or a one-time creation. It’s a platform. A framework engineered for the long-run. The iPhone didn’t and doesn’t need MMS or a better camera or a video camera or more storage or cut/copy/paste or GPS mapping or note syncing, because the framework was in place so that Apple could add these things, and much more, later — either through software updates or through new hardware designs. The way to build a complex device with all the features you want is not to start by trying to build a device with all those features, but rather to start with the fundamentals, and then iterate and evolve."
...click the link for the whole article.