Students are always trying to convince me what great "Multi-taskers" they are. I try to explain that there is no way they can read what is on the board, write or check text messages, and/or learn new material. They are just distracted. I don't have their complete attention; I have their partial attention. When learning new material, having their complete attention is very important.
I think the problems isn't just with students, it's with everyone. I hear about more people texting while driving and more signs springing up at restaurants, shops, and businesses that don't want you to use your IPhone.