After installing Firefox 4, one of the feature which you note will be the missing status bar. Most of the publishers and SEO experts use the SearchStatus Firefox plugin for checking Alexa Ranking and Page Ranking information of a blog or a website. The Firefox 4 by default does not display the status bar and now this can enabled using the View –> Toolbars option.
To unhide the status bar in Firefox 4 (known as add-on bar in Firefox 4) , click View menu and then navigate to Toolbars menu option.
Tick the menu bar with label as Add-on Bar, this would start displaying the Alexa and Page rank information at the bottom of the Firefox window as shown below.
The keyboard shortcut to enable or disable the Add-on bar is Ctrl+/