Nick Haemel has a great short “cliff-notes” version of the new OpenGL 3.3 and 4.0 announcement over at FireUser.com, covering some of the important new aspects in relation to application developers.
OpenGL 4.0 includes all of OpenGL 3.3 plus a slew of new stuff including enhanced blending, indexed drawing from buffer objects and enhanced transform feedback functionality. It also provides access to double precision floating point data types in shaders, key for compute, design, and digital content creation where precision is critical. New texture functionality allows for advanced texture gather fetches, new texture buffer formats and cube map array textures.
He also discusses the new tessellation support and GLSL improvements.
