Youth, we've been told, is wasted on the young. But not on this group. A generation ago, when many of these entrepreneurial whiz kids were still in diapers, starting your own business was considered akin to drifting, occupational flailing. It was the kind of thing your parents would frown upon, and then encourage you to find work in, say, plastics. And then a funny thing happened. The Michael Dells and Richard Bransons of the world--very young people with very big ideas--started to make entrepreneurship cool (not to mention finding fame and millions in the process). In the early 1980s, there were just 270 entrepreneurship courses offered at colleges and universities across the nation. Today, there are roughly 5,000. Some 200,000 students are now enrolled in some type of entrepreneurship class--and that's not even counting those who bypass college altogether. On the following pages, you'll meet five standouts. To meet 25 of their peers, log on to www.inc.com/30under30.
Mark Zuckerberg, 22
Two years ago, as a junior at Harvard, Mark Zuckerberg developed software to help fellow students trade photos and jokes, rant on any topic they pleased, or just say hi--thereby creating a searchable database of personal profiles exclusively for the college set. It caught on. Facebook, the company he co-founded in 2004 and ultimately left school to run full-time, is now the seventh most-trafficked website in the U.S., according to comScore Media Metrix. The site connects seven million (and counting) registered users at colleges and high schools across the globe, two-thirds of the U.S. four-year college undergraduate population. Facebook's reach has attracted big media players--including a rumored offer from Viacom for $750 million in April and speculation that the site was holding out for $2 billion. "The numbers people were throwing around back then were big, and we're flattered by that," Zuckerberg says, adding that the company, which runs on advertising revenue and has 100 employees, was never looking for a buyer. --Angus Loten
Ryan DeLuca, 28
Back in high school, Ryan DeLuca developed passions for bodybuilding and business. It wasn't long before he decided to merge the two. DeLuca's company, founded in 1999 and based in Boise, Idaho, has benefited from a savvy domain-name purchase, and in a crowded marketplace that includes GNC and the Vitamin Shoppe, Bodybuilding.com keeps customers coming back with the online community it has built. Today the site has more than 200,000 members and generates a million page views a day. And while visitors are there, many of them place orders for vitamins, supplements, etc.--helping propel Bodybuilding.com to annual revenue of $46.5 million and No. 230 on last year's Inc. 500 list. --Kevin Ohannessian
Jacquelyn Tran, 29
For Jacquelyn Tran, getting into the family perfume business meant bringing a new approach to selling fragrances and beauty products. After seeing the selling potential of the Web and leaving college in 1999, Tran used a $50,000 start-up loan from her parents to launch Perfume Bay, an online store that sells more than 800 brands of perfume, cologne, and beauty products. With revenue topping $9 million in 2005, Tran says Perfume Bay--where fragrances are described with sommelierlike specificity-- has found success by translating the knowledge and customer service of a department-store makeup counter to the Web. --Ryan McCarthy
Elizabeth Holmes, 22
An estimated 100,000 people die each year from adverse drug reactions. At the age of 19, Elizabeth Holmes designed a device that could prevent many of those deaths. With the Theranos 1.0, patients prick their finger and place a small drop of blood on a disposable cartridge, which is then inserted into a reader that analyzes the medicine in the blood. The device sends the data wirelessly to a secure database, which is available online to physicians. As Holmes describes it, "Theranos 1.0 is an external point-of-care BlackBerry." Holmes, who left Stanford to found the company in 2003, received a bridge loan from a VC firm and private equity funding totaling $6 million. The company recently raised another $10 million. --Jasmine D. Adkins
Jared Issacman, 23
When e-commerce was coming of age, so was Jared Isaacman. In 1999, while the other kids in Far Hills, New Jersey, were shooting hoops after school, the then-16-year-old was working full-time in the IT department of a nearby credit card processing firm. There, he discovered a critical industry secret: "They were 20 years behind in technology and had to outsource almost everything they did," says Isaacman. Soon, United Bank Card, the company he bypassed college to found in 2000, was attracting upward of 300 new clients a month and processing credit card transactions for restaurants, liquor stores, and other brick-and-mortar merchants. Today, United has some 45,000 clients--including Burger King and Ferrari--and annual revenue of $53.5 million. It processes more than $4 billion in transactions every year, earned a spot at No. 19 on the 2005 Inc. 500, and recently moved into ATMs. --Angus Loten
Profiles, videos, and a slide show of our coolest entrepreneurs under 30 at www.inc.com/30under30.