27. Andrew Mason
Andrew Mason
Founder and CEO, Groupon
Age: 31
Industry: Technology

It's been a rollercoaster year for Mason and his daily deal darling. In February, Groupon's Super Bowl ad drew fire for using Tibetans as a punch line. Its June IPO filing drew scrutiny from regulators (and raised eyebrows from everyone else) for unconventional accounting practices -- leading to a change that cut reported revenue in half. Merchants are uneasy, competitors are gaining ground, and the public seems to be tiring of Mason's cheeky humor. But he gets props from us for inventing a category, and Groupon's 115 million subscribers and 92 million deals to date still make him the king of the market.

Last updated October 25 2011: 5:11 PM ET
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