Changes

A private browsing session should be initiated with a menu command called item named "Begin Private Browsing" above "Clear Private Data" in the Tools menu. This option can either change the currently running instance of Firefox, create a new window, or create an entirely new instance of Firefox depending on how this feature is implemented.

Directly after entering private browsing mode, a dialog box or [http://blog.mozilla.com/faaborg/2007/03/06/would-you-like-to-redesign-notification-in-firefox-yes.-not-now.-never./ notification] should display, clearly explaining the scope of this feature. It is very important that the user understands that this feature enables local privacy on their machine, but that their ISP, corporation, or government will still be able to monitor their activities online. We don't want to have whistle blowers fired or dissidents jailed on account of bad UI. We may also want to consider not shipping this feature in certain regions where misunderstandings over the scope of this feature could have serious ramificationsfor the user.

When Firefox is in private browsing mode, the theme should change so that users can tell that they are in this private browsing mode using their peripheral vision. This change in visual appearance could range from turning the location bar black, to the entire browser window.