The extension, Status-4-Evar, will restore the status bar to how it looked before Firefox 4.0. Some people might like the more simplified interface of the browser, but others want to be able to see the status of things in the bottom of the browser all the time. If you find yourself in the second group, this add-on is perfect for you.
Here is a little more information about Status-4-Evar:
Status-4-Evar aims to bring back (some of) the old status bar items, give you more control over the built-in Firefox features, and provide new alternatives. The extension provides “Status Text“, “Progress Meter“, and “Download Status” items. These toolbar items can be moved wherever you want by customizing the toolbars. Behavior of the toolbar items, and other additional settings, can be controlled in the extension preferences.
It should also be noted that this extension can also act as a replacement for the Fission extension. There are preferences to show links, status, and progress in the location bar instead of the toolbar items. Want to give it a shot? You can download Status-4-Evar at the Firefox Add-ons website.