I'm interested in showing people data that they don't normally see. I mentioned VNCCasts in another post. Another example would be to show the web traffic at a web site to everyone in real-time. This might be done using something like http://www.visitorville.com/. Or maybe you would show actual sessions in progress. But whatever you do, the point is to make the site look more active and interesting. It's a way to promote the site.