International Business Times' Daniel Jacobs says a J.D. Power and Associates study finds that overall spending for wireless services has increased significantly since 2004 as consumers try out new non-voice serices. The average bill this year is $66 per month, up from $55 per month in 2004.

"It will be important for wireless carriers to continue to roll out new services and products to increase customer revenue as industry penetration slows and customer retention becomes more critical," says Kirk Parsons, senior director of wireless services at J.D. Power and Associates. "However, customer expectations will continue to rise, as cell phone users increasingly rely on the communication functions of their cell phones beyond voice calling."

"The study also finds that customer satisfaction can impact the actual usage levels of new products and services, particularly for services that charge a fee," Jacobs writes. "For example, the level of regular usage for sending/receiving text messaging among those with above-average satisfaction is 27 percent. This compares to only 21 percent among those who are dissatisfied with their overall wireless service."