The 10 Entrepreneurs Who Defined 2014 Read about the business leaders who dominated headlines in 2014 and set the stage for the year ahead -- for better or for worse.

From game-changing technologies to record-setting IPOs to scandals that would make a starlet blush, this was a year that had it all. Some startups hit the big time; others hit the skids. Entrepreneurs went from zeros to heroes (and vice versa). Here are 10 business leaders who dominated headlines in 2014 and set the stage for the year ahead—for better or for worse.

Tony Fadell

Tony Fadell holds the key to the home of the future. A former Apple executive who spearheaded development of the iPod, Fadell is founder and CEO of Nest Labs, whose Wi-Fi-enabled Nest Learning Thermostat is the shining symbol of the connected-home revolution. The Linux-based thermostat tracks your schedule and programs its software according to your comings and goings, slashing heating and cooling bills up to 20 percent. Three years after it first hit the market, the $249 product has saved users an estimated 2 billion kilowatt-hours of energy, enough to power 180,000 American homes for a year.