Graphite is a free widget for Apple's Dashboard. You give it a website and a number on that site, and it will track and graph changes to that number over time. Here's a few sample graphs.
- Three-click graphs: open a site in Safari, click 'Discover URL,' then 'Discover Text' and click the number you want to graph.
- Multiple lines on the same graph - up to five.
- Multiple instances for different graphs - infinite.
- Automatic scaling - any values between zero and a trillion. (Scaling for very small decimals more...