What does panning do?

To pan an object:

1. On the Display menu or ribbon bar, select Pan. Alternately, you can press Ctrl + F3.
2. Move the pointer and click the part of the site that you want to see as the center of the site.

You can also PAN without doing above, by simply pressing CTRL+SHIFT on your keyboard as you mark out a rectangle on the screen. The site would pan to the centre point of that rectangle. This is often very useful as you don't have to switch the mouse mode.