The document discusses how a shared codebase approach can be used to develop apps for multiple platforms like iOS, Android and Windows Phone. It proposes using portable JavaScript and SQL for the shared application logic layer. Platform-specific UI layers would be built using the respective native technologies like Core Animation on iOS and Qt on Android. Data and events can be shared between the native and JavaScript layers through platform-specific APIs. This allows halving the porting effort while building a more robust cross-platform product by focusing on the UI instead of duplicating the application logic on each platform.