Digg Firefox Extension shows Digg stats for any page
But that's where the similarities end. While Smart Digg Button hangs out in your status bar, Digg Firefox Extension adds a toolbar to Firefox, which makes sense as it has a ton of submenus. For example, you can see the last 10 people who dugg the page you're visiting, and even read recent comments without clicking through to Digg's web site.
You can also forget about the page you're on altogether, and use the Firefox extension to see a list of recently popular, recently submitted, and hot stories. Or you can use the extension sort of like the StumbleUpon toolbar by clicking on "Random Story" to be taken to a random site submitted to Digg.