Shoppers leaving Wal-Mart Stores these days are used to long check-out lines. In a few years, however, those lines well might be history. Wal-Mart is introducing radio frequency identification (RFID) tags to its products – small devices that emit radio waves containing information about product size, price, etc. Though this scenario is still far in the future, such tags could let the world’s largest retailer add up the prices of purchased goods as shoppers leave the store and deduct the tab directly from their accounts. Whether such futuristic practices materialize or not, one thing is certain: RFID has begun to acquire a buzz that positions it as the next revolution in the world of retailing. How real is this revolution? And what does it mean for retailers and customers?…