We mark our notes (most of us with a stamp) enter the serial number on here, then when someone like you finds one and enters it, it tells us where it is and how long it has been out and also how far it has travelled. Anyone can do this, all you need is a stamp to mark the notes with. All the new polymer (plastic) notes need a special ink called STAZON which can be purchased at most craft stores. It is just a hobby to see where your money does travel and how many hands it passes through in it's lifetime. Too bad that everyone who finds one does not enter it, but that just adds to the challenge of the track. Hope you decide to mark and enter your own notes and see where it goes.
AND....It is FUN!