Last week, Amazon.com (NASDAQ:AMZN) handed out 500 new virtual "Coins" to Kindle Fire owners, telling them they were theirs to spend as they will. (At a penny a piece, they're worth a whole $5 -- so go wild.) Much like Apple and StarbucksĀ with their branded, use-only-at-our-stores debit cards, or like tokens bought for cash at a video arcade, Amazon's Coins can be used only one place: Amazon.com.

Why is Amazon inventing a new currency -- and will giving away a few tens of millions of dollars' worth of Coins be enough to get them into regular circulation? In the video below, Fool contributor Rich Smith breaks it down for investors.