Wordle is a really cool tool to create a word cloud of your work. Why is this important for a writer? Well, when you copy and paste your document into Wordle, you see a visual expression of your focus. For example, if you use the word "got" more than anything else, it will be bigger than all the other words. Who wants a piece focused on such a do-nothing verb?
You can also see if your focus/hero is really the focus. If there are other characters whose names appear more often, therefore bigger font in Wordle, then your hero might not be the focus of the story. That could be good or bad depending on how you want to portray your hero.
Besides, as a visual person, I like to see my work condensed down into its most frequently used words. Gives me perspective. And changing colors and fonts is a great mind distraction when you're trying to come up with the next great plot twist. http://www.wordle.net/create