Khronos Details WebGL Initiative to Bring Hardware-Accelerated 3D Graphics to the Internet
Wide industry Support from Major Browser Vendors including Google, Mozilla and Opera; Specification will be Available Royalty-free to all Developers
I think that Google O3D and OpenGL ES success on iPhone games probably combined to get this in motion. OpenGL and very basic video cards are now standard in most machines out there. Unity3D actually published hardware statistics on casual gamers (web-based games) ever so kindly and shows that even though there are some older Intel cards out there, for the most part machines nowadays have a video card capable of supporting at least low-poly 3d and hardware supported 2d rendering in real-time for games, user interfaces and more.
This is exciting news, it appears the movement of the web gaming market is getting much more capable and is accelerating the innovation of hardware accelerating the web.