I've been spending quite a bit of time with some Avalon team members in my new position as Technical Evangelist, and one of the Avalon topics that often comes up is Data (or Information) Visualization. If you're unfamiliar with the term, it might help to read Grokking the infoviz, an older—but still relevant—article from Economist.com. I'm certainly not the person to look to for an official definition, but my own short description would be: "a method of graphically visualizing and navigating through large amounts of data." Most of the compelling demonstrations that I've seen involve some kind of animation that helps illustrate relationships and patterns in the data.
One of our e-mail threads today pointed out a site that uses data visualization to illustrate the popularity of baby names. The application is called NameVoyager. I'm impressed at the simplicity of the interface and the amount of data that can be mined in only a few simple keystrokes. It's also very easy to see the relationships between names. Kudos to The Baby Name Wizard.
Here are some other interesting sites that I've run across in the past that I'd classify as data visualization:
As I alluded to earlier, Avalon enables some very rich data visualization scenarios, and I can't wait to see what people are able to do with it.
I'm sure I've missed some other cool sites...feel free to refer to them in feedback.
Update: Check out information aesthetics for links to some other interesting data visualization sites.