Can I expect users to be able to run software that uses OpenGL 3.x?
Can Linux users who have open-source graphics drviers run OpenGL 3.x? I know that Mesa3D 7.8 only supports OpenGL 2.1.
I also know that OS X Snow Leopard supports some but not all OpenGL 3.0 features. I don't know the situation on Leopard.
I don't know the situation on XP, Vista, and Windows 7.
I'd like to start learning OpenGL, and my interest lies more in scientific and engineering applications than games. I know I'll be reading code that uses OpenGL 1.x, but I'd like to write code using the newest specification I can expect user's systems to support. I'm wondering whether I should start learning 2.1 or 3.3. I was thinking of getting either the 4th edition of the OpenGL Superbible to learn 2.1 or the 5th edition which is coming out July 30 to learn 3.3. (I have a bachelor's in physics, so my math background is pretty good.)
Edit: I found this related question with answers that are relevant to my question.