It's a self-updating, browsable treemap with deeper keyword breakdowns when you click. For example, as I write this, Apolo Anton Ohno just won silver after a crazy finish in the 1500. Click on the related rectangle, and see the related tags and recent tweets. Use the scroll up top to move through time. http://flowingdata.com/2010/02/15/watching-the-pulse-of-the-olympics-on-twitter/
It supports investigation into the relationship between how words are used within the messages of all the people using Twitter.
the data is retrieved a Venn Diagram is shown which illustrates the rate of tweets containing the search terms in the various combinations.
Cadmus is a real-time service that manages your stream (Twitter, FriendFeed and RSS) by displaying the most relevant content since the last time you checked in. It helps you get caught up on what you have missed.