Keyword Density Tool in Firefox

I just discovered a new feature of Firefox that I love. You can right click on any web page and choose "Show Keyword Density" and type in any keyword or phrase, and instantly see a nice keyword density report that covers Title, Meta keywords, Body, Headers, Links, Bold, and Meta description. Having this functionality embedded in the browser will be a real time saver for SEO-saavy web designers and copywriters. Kudos to the person that added this feature to Firefox.