Well I have just started learning Opengl and well I use glut for my window needs. I wanted to know that when professional applications are made under windows, do they use glut for their window purposes or do they make windows made using win32 programming.
OpenGL is just rendering API. To interface OpenGL with OS, you need to create window and OpenGL context.
GLUT is easy-to-use interface between openGL and OS. It is usefull for learing OpenGL. After you reach certain level, you will hit GLUT limitiations and you will wish to roll your own startup code that suits your needs.