Dries Buytaert Acquia Dries Buytaert is programming wunderkind. He learned to program when he was six years old -- even before he could read.

Today he is internationally famous as the creator of Drupal, one of the world's most successful open source projects.

And it all happened by accident.

Drupal is a free, open source content management system that powers a million websites including some of the biggest or most important like the White House, NASA and Twitter. Nearly 790,000 people in 228 countries contribute to it.

"This was never intentional. I'm an accidental leader. I love what I'm doing but never envisioned this to happen," he told Business Insider.

Although he's been working on Drupal for over 12 years, for most of that time, he never made a dime on it. This changed about four years ago when he founded Acquia in Boston.

Acquia is already wildly successful. It provides technical support for Drupal, has a Software-as-a-Service program similar to Wordpress.com and does web hosting via a service called Drupal Gardens. The company has nearly 2,000 customers, with Drupal Gardens hosting over 100,000 websites including huge sites like Arabic news network Al Jazeera.

Acquia has raised $38.5 million in venture funding, backed by North Bridge, Sigma Partners, Tenaya Capital and Tim O'Reilly's O'Reilly AlphaTech Ventures.

"We've grown from two people in 2008 to over 200 people today. We're looking to add another 100 to 120 people," he says. That makes Acquia one of the fastest-growing startups in Boston and named to Forbes most-promising list.

Because Drupal and Acquia isn't enough, Buytaert also has a second startup, Mollom, a comment spam blocking service for use with Drupal sites.

And it all started because because Buytaert wanted to build a private intranet for his college roommates so they could leave messages like when to meet for dinner. It was 1999, Buytaert was 21 and experimenting with new web technologies at the time, PHP and MySQL.

When he moved out of the dorm, he put this project on the Web and blogged about it. People discovered his blog and the Drupal web site and started asking him to add features, so he released it as an open source project so they could do it themselves.

He had some experience with open source. When he was barely out of high school he stumbled across this thing called Linux being built by some guy named Linus Torvalds. Buytaert contributed code to Linux for wireless network drivers.

Torvalds would eventually become one of his advisors on how to make a living from his open source project.

At each point along the way, Buytaert was shocked to discover how big Drupal was becoming. "There were multiple tipping points," he says. In 2005 he organized the first Drupal conference in Antwerp, Buytaert's home town. "40 people showed up. I couldn't believe it. Drupal was was something I would do from my couch at night. To think that 40 people traveled to Belgium to talk about Drupal for a week -- I really felt like it was huge."

But the world really changed when he found out big users had adopted Drupal. "I remember NASA and MTV switching to Drupal. I felt additional responsibility, more weight on my shoulders. Real organizations are now using this to fulfill real business missions."

Drupal isn't the only open source CMS around: there are others, like Joomla and Wordpress. But Buytaert says that in the open source world, these projects collaborate more than they compete.

Drupal is known for extreme versatility. It's even been called "the Justin Bieber of CMS," by one of the contract developers who built Whitehouse.gov. Bieber can sing, dance, and make money.

And, now, thanks to Acquia, so can Buytaert. At least that last part.