I've often thought the marketing companies should just put a chip in our earlobe much the same way naturalists tag animals. Your wallet wouldn't bulge with all the rewards card, nor would you have to carry a giant, jailer's keyring to keep the cards on. The clerk could just scan your ear, and marketing could get all the data needed about shopping habits, and the consumer could get instant reward points and coupons.
The register clerk scanned the coupon code from my phone and then told me I needed Keyring. Keyring is a free app for smartphones that puts all your rewards cards in one place. You scan all your rewards cards into your phone using the app. When you're out shopping, you scroll through your list, show the bar code and the clerk can scan in the code or manually enter the number. No more bulging wallets or cluttered key chains. Brilliant! And it hurts a lot less than have a chip embedded in your ear.