Many commercial companies emphasizes the use of its own products inside the company to convey the confidence in its own product.
Now Microsoft decided to eats its own dog food. Microsoft is preparing a fully Silverlight-powered redesign of their website. This will push Silverlight usage to more users. Silverlight is a runtime for browser-based Rich Internet Applications, providing a subset of the animation, vector graphics, and video playback capabilities of Windows Presentation Foundation. The runtime is available for Microsoft Windows and Mac OS X, with Linux support under development via the third-party Moonlight runtime.
=> More information: Microsoft to Push Silverlight via Redesigned Homepage