New Containers Feature in Firefox
A new feature, called "Containers", has recently landed in Mozilla Firefox Nightly builds.
Read in detail: http://winaero.com/blog/first-look-at...
Every Container, which can include one or several tabs, will have its own set of cookies, local storage and other session related parameters isolated from the main browsing session and other containers. For example, once you are logged in to some web site in one of the containers, all tabs opened in the same container will be able to recognize your session and will show you as logged in to that site.
If you signed in to Facebook with a tab of the Personal container, all tabs from the Personal container will show you logged in on Facebook, however, the main browsing session and Work, Banking and Shopping containers will not show you logged in there.
The best thing about this Containers feature in Firefox is that the set of cookies and other session-related data will be saved between browser restarts. If you signed in to Facebook with a tab of the Personal container, then closed the browser, the next time you open it, the Personal container will keep you signed in to Facebook. This gives the Containers feature an edge over Private Browsing sessions.