Muhammad Saleem of Pronet Advertising has a run down of three different Firefox extensions which optimize your Digg.com experience.
First is the Digg This! Firefox Add-on which lets you select highlight text and submit an article to Digg with only the right click of the mouse.
Another Greasemonkey Add-on adds a link to the DuggMirror page of an article (incase that article is down due to the Digg effect).
I’m sure you will agree that it is quite disappointing to see a story on the front-page of the site that looks interesting, only to click it and find that the site that was hosting the content has gone down due to the Digg Effect. Of course you could go to DuggMirror and look for a cached version of the story there, or click on a link to a cached version of the story posted by someone in the comment threads. But why even go through that trouble when the process can be automated for you?
The third is DiggTaggr which analyzes the story the user is viewing and displays additional related stories.
More from Pronet Advertising’s post; Optimizing Firefox for Digg.com