Touchgraph (the website has now got a facelift!) and the TG-GoogleBrowser was one of the early visualization products I played with to visualize sales data.
Here are some pictures that tell a thousand words...
- The search clock by Chris Harrison which looks at search trends from 1997 to 2000
- The Wikipedia power struggle by Bruce Herr and Todd on what's happening on Wikipedia
- Clusterball by Chris Harrison visualizing Wikipedia