In Japan you can do just about anything with your cell phone, except talk on it. You can pay for nearly everything with your cell phone: train fare, groceries, drinks (or cigarettes, beer, porn magazines, eggs) from a vending machine. I've even seen cell phones with a built in pedometer! A Japanese university recently starting having complete classes via cell phone using text messaging!! And there are Japanese authors publishing entire novels completely via cell phone texting.
But Japanese people NEVER talk on their cells in public, it's considered extremely rude; if it's absolutely necessary to take a call you'll see the person remove themselves as far as possible from other people, turn their back and speak quietly into the phone while shielding their mouth with their hand. On the trains and buses there are signs and frequent announcements reminding everyone to put their phones on vibrate.