Starbucks is partnering with mobile-payment company Square to save money on credit- and debit-card interchange fees and to give customers a second option for paying for their lattes by cellphone. As part of the deal, Starbucks will invest $25 million in Square, and Starbucks CEO Howard Schultz will join its board of directors. Customers who have Starbucks cards already can deduct money from them using a Starbucks app on their cellphones in the U.S., Canada and the U.K. That app launched in January 2011, and handles more than a million transactions each week.
