Indeed, and what makes it interesting is that the information can (and should) travel in both directions: just as I want to know what my dollar has done when I

Indeed, and what makes it interesting is that the information can (and should) travel in both directions: just as I want to know what my dollar has done when I buy an apple (e.g. I paid starvation wages to farmers and justified clear-cutting of a piece of rain-forest, gave political contributions to some dictator, etc) and the vendor gets to know how I earned that money (e.g. an office job where I make software content that tricks users into giving up more personal info, ultimately to get a higher ad price). You run into a technical issue in that you can trace a dollar indefinitely in both directions. But perhaps there's a solution, like some sort of decay.