I'm at Can Visualization help?, probably the session I was looking forward to the most. It's headed by Fernanda Viégas and Martin Wattenberg, who've done some brilliant and badly needed work on Wikipedia visualizations, and Ben Shneiderman, expert in the field.

Fernanda Viégas: Live demo of history flow! Revert wars look like zigzags.

There's a new version that lets you zoom. And they're going to make it possible to use history flow with new wikipedia data (which hasn't been possible for awhile).

Martin Wattenberg: How can you get a picture of what a wikipedian works on? His visualization looks at all the edits of a particular user. These are beautiful snapshots of personalities, a little like poking through someone's bedroom. (For that reason, there are questions about whether tools like these should be released publicly. I hope they are, because they're utterly awesome.)

Ben Shneiderman's talk is about the field of visualization in general (and is targetted at businesspeople who aren't as computer-savvy as this audience -- one gets the feeling it's a presentation he's given before). Anticlimatic after Viégas and Wattenberg. But his intro is good: Using vision to think. "Visual bandwidth is enormous: Once you train your eye and your mind you begin to see it there quite naturally."

Viegas, relatedly: "People felt like they actually got it after they saw these visualizations. People who had never looked at wikipedia before could pick up on those patterns as well...From experience, the impact of showing this to people is just amazing."