Timeline-Based Tag Clouds
Chirag Mehta has created a Tagline Generator that allows you to see the changes in tag clouds over a variety of documents. In addition to seeing the tags (or in this case, the words used in a document) and their frequencies, there is also a slider, which allows you to scan the tag clouds created from other documents. It makes more sense if you see it.
One of the demonstrations uses the US Presidential Speeches. You can see how the focus of the speeches moves from “assembly,” constitution,” “colonies,” and “independence” (Adams and Jefferson) to “imports,” “value,” “export,” and “treaty” (Harrison) to “terrorists,” “iraq,” “economy” and “weapons” (George W Bush).
You can download and install it yourself . It’s an interesting way to look at history and/or documents.