[magnitude]

I like 3, but I'm not sure how it would be executed but you would first need crazy volume. Please push forward on it! I'd love to brainstorm with you for fun. It seems like it would need to be one of those things that came as a side effect of something else you were building. Not sure.

You would have to do the tracking independent of the owners of the penny, of course.

And there is more value to this than providing a new negative feedback loop. If someone believes that the source of the money is just as important, if not more important, than the amount of money, then such a history is very valuable to them. For example, I'm sure there are some religiously organized charities that don't want mafia money for donations, especially if such money was going to fund construction for a house of worship, etc.

I see this as being potential very valuable in the oil-rich Gulf countries.

On 2, how is this different from salary.com. Maybe one of its competitors have an API you could use.