For current AT&T's customers, there is no change. They can choose to switch to Mobile Share, or they can continue to use, upgrade or downgrade their existing plan.
Generally, customers subscribing to shared-data plans might be less inclined to switch to another carrier if their cellular service for several devices, including smartphones and tablet computers, is attached a single plan.
Carriers also see the plans as a way to encourage subscribers to add more devices and increase how much they spend on cellphone service.
Competition is ramping up in the U.S. wireless industry. AT&T is facing aggressive competition from No. 4 U.S. operator T-Mobile US Inc.