I bought this on a whim. The concept sounded interesting. But it fails quite magnificently. The cards are poorly designed. They aren't designed to last, and yet the whole purpose is to pass them on, leave them in potentially weather-torn locations, and carry them in your pocket regularly. The track code is essential to make the game work. But it's pasted at the bottom of the card, in a smallish font, and looks like it is entirely irrelevant. It doesn't explain to the person who finds the card that their task is to visit the website and then enter the code. Rather, it just gives the code. Underneath, it does give the website address, but because it's in a different colour it doesn't look related. And the code is preceded by "Track this card:", which sounds like it's only relevant for the person who gave the card (to be able to track it), not for the person who receives the card. I thought a simple way to clarify this would be to draw an arrow between them, which might suggest they are related. Apparently, that's too subtle. I have given a number of these cards out, but only one or two of them have been tracked.
What's more, the cards are supposed to be continuously passed on. But the cards don't explain that very well either. It's as though, as a receiver, you simply pick up the card, maybe go to the website (if you're curious to know what the code means), and then bin it. It's not at all clear that the card should be passed on again and again. I've yet to have a card pass on to a second person