What's a wordle?

I found out about a cool website through Cindi Trainor's blog.

Wordle lets you create tag clouds out of whatever words you want. The results are rather neat and professional looking. You can play around with the layout, font, and colors. While the options are limited (I'm not too happy with the color schemes available), this application lets you feel like a computer pro.

I created a wordle out of Wendell Berry's Country of Marriage. Have a look at it here.

I'd like to create one out of a poem or passage about libraries.