I just discovered that and I have to share it with you as it's a awesome tip. While using firefox, one of the greatest functionality is the tab browsing, a click on the scroll button (la molette) over a link will open that link in a new tab, but what to do with your notebook... right button and then open in a new tab... it's a bit painful whereas you just have to click with two fingers on your touch pad and here comes back the awesome functionality!!! Just so practical!!! And also alt + arrows to get back/forward on the history of browsed pages!