Square Planning Big Mobile Payment Rollout, Could Be Bumped by Newer Tech

A stutter in the rollout of Jack Dorsey's novel Square cellphone credit card system may mean it'll get swallowed soon by emerging tech.

The Twitter cofounder's tool has been in and out of the news for months, largely because it appears blindingly simple, and comes with promises of radically reinventing the mobile credit card payments scene. The device is incredibly straightforward: It's a tiny plastic gizmo with a magnetic strip card reader inside, a smattering of circuitry, and a standard...