"In the most ideal class settings, mobile devices disappear into the background, like markers and whiteboards, pencil and paper – not because they’re not being used, but because they’re simply tools, a means to an end. The “end” can be any number of things: to gauge student understanding of a concept, to capture notes and ideas to be used and studied later, to calculate, to communicate, to express ideas."
Many schools still ban cell phones. They do this because they see them as a disruption in class and a distraction for learners. Sad, but true.
So when does it work? It works when teachers incorporate the use of mobile devices as a tool to support learning in the learning activity design!