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Apple incorporated one into Passbook with iOS 7, but iirc it only works with links to Passbook. Try it out and see if there are any changes there.
 
BlackBerry App World had one included two years ago. Not sure about android or windows, but if they do as well, Apple has no excuse! Other than barcodes aren't as common as they were a few years ago. They're really pushing this iBeacon thing that just appears on your phone with no need to scan anything.
 
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