Zaid Farooqui cofounded Web design company Cyquester Technologies and hired an employee in India for $400 a month - when he was in the ninth grade.
Steven Bao sold a Facebook program to a Silicon Valley venture capitalist and started the Facebook Developers Meetups in Boston this summer, while reading "The Grapes of Wrath" for 10th grade honors English.
There have always been ambitious young entrepreneurs - Bill Gates dropped out of Harvard University to build Microsoft, and Larry Page and Sergey Brin left a PhD program at Stanford University to launch Google.
But thanks to cheap bandwidth, online advertising, broadband access, and the ability to spread ideas through blogs or social networks, even younger people with little funding and few connections have been starting Internet-related companies in recent years.
"In the old days, the entrepreneurial avenues that were open to you could have been a paper route, mow the lawns in your neighborhood, or have a lemonade stand," said Lee Lorenzen, chief executive of Altura Ventures. Altura bought Bao's application, which allows people to post virtual badges showing they have iPhones on their Facebook profiles, and had to add an extra line in the purchase documents so his parents could sign for their underage son.
Entrepreneurs who launch companies in puberty are anomalies, but the Web has lowered the bar for people with skills and ideas. People don't need a development team or a big budget - they just need a good idea and a laptop.
"The cool thing is it's becoming more and more common," said Farooqui, 20, who spent the summer in Cambridge working on iJigg.com, a music-ranking website that boasts 10 million song plays each month, and is moving to Silicon Valley to seek financial backing with his 25-year-old brother and co-founder Shadab. "Doing an Internet startup is like having a band - that's my basic theory. Everyone will have them because more than anything, it's fun."
The Farooqui brothers got a boost from spending this summer in Cambridge with Y Combinator, a combination of small-scale venture firms that operates like a startup camp for people with big ideas but little business experience.
Y Combinator, started by entrepreneurs in 2005, helps companies incorporate, introduces fledgling founders to investors, and doles out funds to the budding moguls who participate in its weekly dinners, giving striving entrepreneurs a community. Typically, the firm provides startups $5,000, plus $5,000 per founder, in exchange for a 6 percent stake in each company. The average entrepreneur in a Y Combinator session is 25, and he or she need not have an advanced degree, connections, or work experience.
Jessica Livingston, a cofounder of Y Combinator, said "we did have an inkling" that "the face of entrepreneurship" was changing and that younger people were going to be launching startups. "It was cheaper to start one, and you don't need to ask permission" from investors, she said.
At 18, Aaron Swartz merged his first startup with Reddit.com, a website that ranks news items according to user preferences that was founded by two recent college graduates, at Y Combinator. Last fall, it was acquired by Condé Nast.
At the technology conference TiEcon 2007 in Santa Barbara, Calif., the chief executive of Elementeo, a company that makes a game involving battling chemical elements, took the stage. Anshul Samar, 13, hopes to make $1 million in revenue by eighth grade.
Bao, 15, who chose books on programming over an Xbox when he was 10 years old, is working on a number of projects, including a digital student life organizer and Facebook applications. Though he needs to catch a ride from his parents when he goes to networking events, he has a formidable profile on LinkedIn, noting that he specializes in financial management, Web development, and human asset management - that must be when he's not doing his summer reading or participating in student Congress or Key Club.
In Andover, William Morse, 18, has filed a patent application for his "hard drive zapper" - a device made of recycled disposable cameras that promises to kill a hard drive when a computer is headed for the dump so that identity thieves can't recover personal information.
Morse started refurbishing computers and selling them on eBay, hoping to accumulate enough cash while he was still living at home with his parents to create a seed fund for some of his ideas. He worked out a deal with the local CVS to buy used disposable cameras for 20 cents apiece, found a manufacturer, and then "my grandmother gave me like $100 for my birthday, so I used that to file for patent pending."
Other young entrepreneurs skipped small projects and moved straight to successful businesses.
Sam Altman, 22, cofounded loopt, a company that uses location technology to turn cellphones into friend-finders, with $6,000 while he was at Y Combinator the summer after his sophomore year at Stanford.
He went on to raise $5 million and make deals with Sprint executives - even though when he flew to the Midwest for business meetings he went via St. Louis to borrow the family car since he wasn't old enough to rent one himself.
"I still get carded for R-rated movies occasionally," Altman said.
Carolyn Y. Johnson can be reached at email@example.com.