One of the new features in Apple's iOS6 release due this fall is an enhancement to the FaceTime video call feature, allowing it to function on any cellular network. Friday, AT&T announced that the privilege only extends to users on its new "Mobile Share" programs, and not for users grandfathered on the unlimited or tiered data plans. Public Knowledge, a nonprofit Internet law group, believes that preventing other customers from using FaceTime violates net neutrality rules by blocking a service that competes with its own.