By Arik Hesseldahl, Olga Kharif, Douglas MacMillan, and Rachael King

The Finalists

Once again, Bloomberg BusinessWeek's editors and writers have surveyed the tech sector to identify a fresh crop of the most promising technology startups and the young people, age 30 and under, who are steering them. We assembled this year's list by weighing input from venture capitalists, angel investors, our readers, and our editorial staff. Each slide lists the company name, executives who are 30 and under, a business description, and the toughest decision executives have had to make in the past year, where applicable.