Mac only: No longer must Mac users move to the keyboard to open links in a new tab — free, open-source app MiddleClick sits in your menu bar and allows you to use three fingers to middle click on Apple's multitouch devices.
MiddleClick is a great option for those that are still missing this integral browsing feature on Apple machines lacking multitouch touchpads and Magic Mouse, but don't want something as complicated as previously mentioned BetterTouchTool. Running the lightweight app allows you to use three-finger tapping or three-finger clicking as a middle click, just by picking one in its menu. Unfortunately, this only seems to work in apps that already have middle clicking features built-in, like most browsers — there doesn't seem to be a way to set this to open the dashboard or otherwise customise it in OS X as you could a secondary mouse button, but for those that have been paining for this feature in their browser for a while, MiddleClick is a welcome change.
MiddleClick is a free download, Mac OS X only. Thanks, Rosydoodles!