EBay announced it will split from the payments service PayPal, forming two independently traded companies beginning in 2015. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

A Nordstrom salesperson shows a customer an online selection of shoes on an in-store iPad. Like some other retailers, Nordstrom is using mobile devices to make on-the-spot sales and check companywide product inventory instantly. Courtesy of Nordstrom hide caption

itoggle caption Courtesy of Nordstrom

A barista processes a customer's payment using Square, a device that turns a mobile device into a card swiper. More businesses are using the devices to simplify credit card payments. Others are embracing technology that allows consumers to pay with their cellphones. Jeff Wheeler/MCT/Landov hide caption

itoggle caption Jeff Wheeler/MCT/Landov

Square allows merchants to accept payments automatically from recognized registered customers. Square screen grab hide caption

itoggle caption Square screen grab

David Marcus, president of PayPal, unveils PayPal Here in San Francisco in March. The service allows customers to use their smartphones to pay for purchases at retail stores. Kim White/AP hide caption

itoggle caption Kim White/AP