Hugh Pickens writes "The WSJ reports that a new device, now in use at about half of Ahold USA's Stop & Shop and Giant supermarkets in the Northeast, is making supermarket shoppers — and stores — happier. Looking like a smartphone, perched on the handle of your shopping cart, it scans grocery items as you add them to your cart. And while shoppers like it because it helps avoid an interminable wait at the cashier, retailers like it because the device encourages shoppers to buy more, probably because of targeted coupons and the control felt by consumers while using the device. Retail experts predict that before long most of these mobile shopping gadgets will be supplanted by customers' own smartphones. As more customers load their smartphones with debit, credit and loyalty card information, more stores will adopt streamlined checkout technology."