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Passbook is essentially useless without industry support
Designed to get you to your plane quicker and receive discounts at coffee stores, Passbook was meant to be the killer feature for developers to hook their apps into. You could ditch those paper coupons or plastic cards and use your iPhone to get the scoops and deals. But hardly anybody uses it. Granted, Starbucks remains the largest user of the service, but without wider developer support, its potential is going widely untapped.