Mozilla did away with the Status Bar in Firefox 4 in an effort to increase screen-space. Instead they replaced it with an optional Add-on Bar. This is not the same as the status bar since this only displays icons/buttons for add-ons. Starting with Beta 7, connection status messages were eliminated and link targets when a link was moused-over were displayed in the address bar.
This change did not go over well with testers and Mozilla faced a lot of negative feedback about this change. So much so that in Beta 11, connection status messages were shown as an overlay above the add-on bar. Then in Beta 12, link locations were also displayed as an overlay above the add-on bar.
By default (again to save screen space) the add-on bar is not shown by default. To display simply press CTRL + / to un-hide/hide the add-on bar.
The new add-on bar displays icons related to your add-ons (such as AdBlock Plus, Brief, Greasemonkey, etc.)
For those who still want the ‘old’ status bar where connection status messages and link targets are displayed, there is an extension for that! Status-4-Evar will replace the add-on bar with the old status bar.
