Steve Stoute, founder and CEO, Translation Advertising (l) and Clara Shih, co-founder and CEO, Hearsay Social

Photographs by Robyn Twomey @FortuneMagazine - Last updated July 31 2012: 1:03 PM ET
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The engine is here to stay

Much has been said about the death of the internal combustion engine. That won't happen any time soon says Caterpillar boss Doug Oberhelman.