The MileWideBack extension (update.mozilla.org listing) for Firefox popped up recently on update.mozilla.org and with a name like that I had to check it out. And whaddya know, it turns out to be yet another essential extension (as far as I'm concerned). The premise of MileWideBack is simple: you use the left-edge of the Firefox window to navigate back and forth in your tab history.
This extension allows you to navigate back and forth without requiring complex hand-to-eye coordination.
"Complex hand-to-eye coordination" may sound amusing at first, and while I can certainly hit the back and forward buttons without a thought, but if you think of it these buttons are really, really small compared to the vast wasteland that is your maximized browser window. Particularly for my case, where I like to "Use small icons" for the buttons in the Firefox toolbar to save on vertical screen real estate.
These little buttons take up really minimal space in the browser, as the screenshot below shows:
Fitt's Law would suggest that it will take a long time ("long" in relative terms) for someone to find and hit those small buttons (but somehow I get by because I'm probably on the computer way too long for my own good). MileWideBack in a sense throws Fitt's Law out the window by allowing you to navigate back and forth by simply "throwing" the mouse to the left and then right-, left- or middle-clicking. (I say Fitt's Law doesn't really apply because it takes constant time to move to the extreme left of the window when no aiming is needed.) You right-click to go back, left-click to go forward, and middle-click to reload the page.
Neat little extension, isn't it?