Have you seen TwitSprout's Obama Dashboard?
Obama held a Town Hall via Twitter in early July. You can see the full analysis here; or look take a look at how the infographic breaks-it-down and highlights some interesting details.
Here is the link for the interactive version. The infographic was created by Dan Holowack at TwitSprout.
This is an interesting use of Twitter, data-mining, and the real-time analysis of big data. I imagine we'll be seeing a lot more of services like this.