Trevin pointed to a cool site called Wordle, where you can enter a bunch of text and the web app then creates a visual image representation of the text, where the most commonly used words are larger. You have control over many aspects of the visualization, such as font, colors, layout direction, removing common words, how many words to display in the image (default is 150), etc.

I copied the text from the home page of my blog just before posting this and used Wordle to generate the image below. It's interesting to see what words flat to the "top" of the list. Makes me thing that maybe you can tell something about people from their writing, and as such from the words that dominate what they write.

You can make your own at http://wordle.net, and see what you learn about your own writing. There's also a gallery of wordles created by others, which I got quite caught up in for a while, reading what others have created. Wordle was created by Jonathan Feinberg, who works in IBM Research with the Collaborative User Experience group.