Less than three months after Starbucks introduced a way for customers to pay for grande lattes using their mobile phones, the Starbucks Card Mobile app has been used by more than 3 million people, the company recently announced.

Starbucks chairman and CEO Howard Schultz spread the good news at the company's annual shareholder meeting. Starbucks Vice President Brady Brewer later called it "the nation's largest mobile payment network," according to a report from Mashable and USA Today.

The Starbucks Card Mobile app, which is available for both the Apple iPhone and Blackberry devices, lets customers "touch and pay" for their purchases. Like the long-standing Starbucks Card, users add cash to their account, but instead of keeping a plastic card in their wallets, users hold their phones up to a scanner, which recognizes a unique barcode the app presents on the phone's screen. The purchase amount is then deducted from the customer's account.

Starbucks rolled out the app on Jan. 19. It can be used in all of its 6,800 company-owned stores in the United States, plus another 1,000 locations inside Target retail centers.

Purchases through the app qualify for Starbucks' rewards program, which allows customers to earn free drinks. The app also helps users find the nearest Starbucks store.

Cashless mobile payment systems are popular around the world, especially in countries that do not have strong banking systems, but they have been slow to take off in the U.S. According to a report yesterday from The New York Times, one of the reasons the technology has not flourished in this country is behind-the-scenes fighting between banks, credit-card companies, telecommunications companies and new payment players like PayPal.

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