The first was the rising popularity of card-based tender options in international markets.

FORBES: Playing the Rebound in Consumer Spending

The consumer places his or her mobile device under the imager, the 2D barcode is read, and the POS treats the tender like a gift card, following the usual payment verification procedure.

FORBES: Apple, iOS 6 & Mobile Payments - One More Thing for the iPhone 5?

Taken another way, the Starbucks Card accounted for 25% of all U.S. tender, the company noted on an earnings call.

FORBES: Starbucks' Secret Recipe for Growth