After our Web site readers nominated entrepreneurs in the U.S. who met two requirements—they were young and running their own businesses—we narrowed the field to the 25 most impressive. Compared with our previous two contests, this year's U.S. nominees included more women, more co-founders, and fewer business-to-business ventures. European readers have already chosen a winner: Aodhan Cullen, 24, who launched StatCounter, a Dublin-based Web analytics startup, when he was just 16. Voting for the American and Asian winners begins on Oct. 22.
Like entrepreneurs of all ages, many of the finalists wanted the independence and challenge of running their own companies. Gabriel Erbst, 24, is co-founder of TableXChange, an online marketplace for restaurant reservations in New York. The business takes a 12% cut of each transaction, though it got its share of criticism from bloggers and local foodies when it launched in June for selling reservations to top restaurants for $20 and up. But Erbst says it is growing and will soon begin taking ads. "We're huge food enthusiasts, so it was great to leave our banking jobs and devote ourselves to this full-time," says Erbst. "It's thrilling to be in control."
Among those finalists taking new approaches to traditional businesses is Sarah Schupp. The 25-year-old founded University Parent, a Boulder (Colo.) company that produces free, downloadable guides for parents visiting their kids at college. Schupp, who expects revenues of $800,000 in 2007, attributes her success in part to an innovative publishing model in which her university partners are responsible for content and distribution, while she handles advertising.To find profiles of our 25 finalists and vote for your favorite, visit businessweek.com/go/sb/under25. By Nick Leiber