I noticed recently while using gmail that you can track the ip address from where you have logged in. This can be harmful for impersonators or people using someone else password to login in. Since the valid person if he is computer literate can come to know exactly who has logged into.
But you bypass this using torpark web browser. You also can configure different countries over that in some editions of this browser, if I am sure. Check it out.
http://www.download.com/Torpark/3000-2356_4-10586817.html