commonly used by those bastard file sharing people...
Basically take for example a VPN provider like PIA....You will have an icon in your windows taskbar tray that if you right click will give the option to enable or disable the VPN service.. When enabled you also get a drop down of countries that you would like to choose from to show where your IP is/where you are connecting from...Then this same IP is shared by 100's or 1000's of other people.
So basically I am in USA, but i can show my IP and location as being pretty much anywhere in the world.