Some high-end Windows specific features of WPF, such as real 3D, hardware-based
video acceleration, and full document support, will not be supported in
Silverlight. This is by design in order to serve Silverlight’s cross-browser,
cross-platform reach scenario that demands a light weight plug-in. That being
said, Silverlight will offer a uniform runtime that can render identical
experiences across browsers on both Mac OS and Windows.