The standard can now handle per-sample effects by the pixel, process shader subroutines for increased programming flexibility, and render content with 64-bit double-precision for better accuracy. OpenGL 4.0 also integrates well with OpenCL to allow certain tasks be offloaded from the typically overworked CPU to the GPU.
Naturally, OpenGL 4.0 adoption will depend both on video chipset makers adding support to their drivers in addition to games and developers creating software that makes use of the new features. On the other hand, OpenGL ES, the mobile offshoot of OpenGL is also expected to get at least some of the new capabilities in the future and could result in smartphones with much improved graphics as the hardware catches up.
In the meantime, the Khronos Group also launched a stopgap OpenGL 3.3 specification that will enable "as much OpenGL 4.0 functionality as possible" on previous-generation video cards.