From the Department of Nifty: If you have multiple tabs opened in Firefox and hover the mouse over one of the tabs, the mouse scroll wheel will allow you to scroll through the open tabs. This is cool. I have a folder bookmarked with all my daily blog reads, and I use the “Open all in tabs” feature to open all my favorites once or twice each day. Being able to scroll through them using the mouse scroll wheel is way, way cooler than using the left and right arrows on either end of the tab row.