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.