Where's George?

No, I don't mean a political slogan from the 90's. Somebody had the clever idea to track dollar bills on the internet. Go to www.wheresgeorge.com where you can enter the serial numbers of a bill in the US or Canada and then follow it later if someone else also enters the number. There are about 76 million bills being tracked this way, and according to a Science Daily article scientists are using the site as a way to predict how disease spreads. The map below shows one of the most travelled bills.