Internet Explorer for instance, allows you to use a new session so that you can log in to the same service with multiple accounts - which is great for Gmail, Yahoo and so on. Unfortunately, Firefox doesn't have this feature implemented for now. But there is a Firefox extension called CookiePie which enables something close to this "new session" feature.


Using CookiePie, you can right click a tab, select "Toggle On/Off CookiePie" and when you turn it on, you can basically log in to a website to which you are already logged in, into the same Firefox window.