1. A method for extending an application type included as a component of a self-contained desktop file, said method comprising: associating an application extension with a platform-dependent software application; receiving platform specific data used to execute the platform dependent software application; storing the platform specific data in the application extension, wherein the application extension is adapted to be executed from a platform-neutral shell operating environment running on a computer system; and packaging the application extension as a component in a self-contained desktop file, wherein a self-contained desktop file is adapted to be received and deployed in the platform neutral shell operating environment running on the computer system.