“News has now been leaked that Microsoft has enabled support for OpenGL to work with the Windows Vista compositing desktop, as of the most recent preview build. Previously Microsoft’s plan had been force OpenGL to be translated to Direct3D, reducing performance by 50% and locking the OpenGL version to 1.4 only.”
http://blogs.msdn.com/kamvedbrat/archive/2006/02/22/537624.aspx
personally i think it was just a marketing ploy to make developers jump ship from opengl to directx, while they had planned to support ogl anyway :).
