With a surprise partnership between Starbucks and Square putting digital wallets in the spotlight, smartphone-enabled payments may be on the verge of reaching the mainstream. The Seattle coffee ...

The plastic card is all black, and save for the card holder’s name emblazoned on the face, features no logos–not even Square’s. On the surface, the deal seemed like a win-win. To Starbucks ...

In one of the largest mobile-payments rollouts yet, technology start-up Square on Thursday said it has begun processing all credit card transactions at Starbucks' more than 7,000 U.S. storefronts.