The real question is whether you want to invest the time needed to create a fallback for those users. Websites that use the new CSS things as a primary thing (like this presentation) won't work, but sites where the newfangled CSS things are used just as embellishment - dropdowns, sliding menus, spinners, you name it - will remain functional, just not as pretty.
Comments
If only every browser implemented it...but IE 7,8,9 are stuck on the old APIs. They're a large percentage of all users.
actually...
IE7: 0.5% worldwide
IE8: 8.65% worldwide
IE9: 5.29% worldwide
http://gs.statcounter.com/#browser_version_partially_combine...
Depends on your demographic. 20% of our site visitors use IE8 :-(.
The real question is whether you want to invest the time needed to create a fallback for those users. Websites that use the new CSS things as a primary thing (like this presentation) won't work, but sites where the newfangled CSS things are used just as embellishment - dropdowns, sliding menus, spinners, you name it - will remain functional, just not as pretty.
tl;dr graceful degradation / enhancement.
It says css 3d, which those browsers doesn't support.