Today’s add-on is SiteLauncher:
A simple Firefox add-on that gives a highly convenient and clutter-free method to quickly open websites that you need often. One keyboard hotkey makes the “Launcher” panel instantly appear, followed by a single key press to jump to the site you wish to open
Meaning instead of re-typing websites like Google, Youtube, Gmail, or Twitter, you can simply create a keyboard shortcut to that URL (ALT + Shift + the shortcut’s assigned letter is default). You can also assign a hotkey (CTRL + Space Bar is default) to open a menu that appears over your browser. To the right is a screenshot of SiteLauncher in action.