hmm, very interesting!
i think having an easily identifiable compound / element / electronic chip in currency is a logical step for a government to take. it would provide a way to reduce trading in mass amounts of cash, perhaps this is a move to crack down on tax avoidance and dealings of illegal goods.
this would push people towards using electronic money, perhaps because it's easy to trace where it goes and prove it's legal.
this could also push a reemergence of bartering
cash is normally used for buying little things where it's too much effort to use your credit card and provide your signature or areas where electronic transactions aren't possible, like a garage sale for instance. having something traceable in cash could make this principle more concrete.
i wonder if this is a step towards phasing out physical money?
i think it's really satisfying being able to physically holding something that in itself is worth nothing, but represents in which people have mutually agreed. i would be quite upset if we moved to card scanning and fingerprint id to exchange for good and services
on the flip side, when - not if, 3rd parties get their hands on a scanning device that could detect a particular currency, it would create more crime than it helps prevent. (perhaps more so in terms of occurrence, rather than like big drug trades in cash)
also on the topic of money:
what happens when your at the airport, and there is that little check box that that says are you carrying more than x amount of cash with you?
what's the go with notes, represententing money. does a $20 bill really represent $18 plus the $2 (just a guess) it costs to produce? how does this factor in with what the currency is worth.
also, is all the electronic money backed up somewhere physically? is every last dollar that's in the economy backed up with a coin or note somewhere?
sorry if this is a bit all over the place

if your interested in this, or don't want to post because it's off topic, feel free to email me (naythis@yahoo.com)