EuroBillTracker  
   Allows users to track Euro bills as they travel. Includes diffusion, tracking, and participation statistics.
   http://www.eurobilltracker.com/

Where's George  
   Track US dollar bills as they travel across the country.
   http://www.wheresgeorge.com/

Where's Willy?  
   Tracks Canadian dollar bills across Canada and the U.S.
   http://www.whereswilly.com/

Canadian Money Tracker  
   Site for tracking Canadian paper notes as they "travel" across the country. Also allows for tracking of high/low notes.
   http://www.cdn-money.com

EurotraQ  
   Allows tracking of Euro notes and provides a list of the bills which have been tracked the most.
   http://www.eurotraq.com/

subnote  
   Claiming money as a public space and property, subnote tries to recode the singular value attached to the promissory note. As the money is yours and ours.
   http://www.subnote.net

Track your cash!  
   A site to watch specially marked bills travel around the United States
   http://stepon.com

SEK Tracker  
   Track Swedish bank notes.
   http://www.sek-tracker.se

Where Have I Been?  
   Tracks Canadian and American paper currency as it circulates.
   http://www.wherehaveibeen.com/

Track My Cash  
   Want to see where you money has been, where it goes after you spend it? Register your bill at www.trackmycash.com and get updates when your bill gets a hit.
   http://www.trackmycash.com

My Euro  
   Allows users to track Euro notes across Europe by entering the serial number and postal code. Includes statistics and discussion forums.
   http://www.myeuro.info/

EuroTracer  
   Allows tracking of Euro notes and offers statistics on bill and coin distribution.
   http://www.eurotracer.net/