In addition to displaying the scene from particular axes, Blender lets you use the Numpad to revolve around the center:
Pressing the 7 key, you shifted to the top view. This let you see how pressing the 4 key rotates the view counter-clockwise. Pressing the 6 key rotates the view clockwise. This is useful when you want to inspect an object carefully. It lets you rotate around the scene in 15 degree steps and the motion is repeatable so you can easily return to an earlier angle if you want.