11 Big Ideas to Watch in 2011

Yoko Furusho
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4. Cash, Credit, or iPhone?

The cash register is still ubiquitous, but it has new high-tech cousins. Twitter inventor Jack Dorsey's next start-up, Square, uses a cheap plastic attachment that turns an iPhone into a sophisticated point-of-sale system that can be used by any business, large or incidental. A host of other new companies are offering novel ways to pay, chiefly using smartphones: self-checkout apps, credit card chips embedded in phones, and a new offering from PayPal that allows money to be transferred by bumping two phones together. Fist bump! (Gently.)