silverlight 3 supports "out-of-browser experiences", i.e., silverlight applications can be installed to the system for offline access (provided the application manifest is designed to allow local installation) where they run outside the browser. they are launched using the start menu or desktop shortcuts, and run without the browser window. applications can check whether they are running inside a browser or not. when running outside of a browser, html interop is disabled. in addition, access to the function keys is enabled. locally installed silverlight applications still run in a sandbox.