Wonderful article in C&RL News from this month, October 2011. Talks about the 'word cloud' website Wordle - www.worlde.net. Enter the URL for any website or blog or for any document or just cut/paste of text and it gives you a VIEW of what you have. It shows the frequency of words found by size. Quite a fun site.
Take a look at the Find & Learn word cloud created by simply entering the link to this blog.
Some of the library databases already use this kind of array for database searches, but I think this tool will widen the application - even for challenging & fun views of various websites or documents.