The Internet encyclopedia has grown explosively since its creation five years ago, with visitors doubling every four months. Its 5 million entries in 200 languages have been written entirely by volunteers.
It's open because most anybody can log on, contribute to, or change a Wikipedia entry. Recently some of these anonymous volunteers gathered to meet face-to-face and celebrate their information revolution.
"We're a bunch of geeks," Jimmy Wales, the inventor of Wikipedia, told Sunday Morning correspondent Serena Altschul. "I mean, writing an encyclopedia as a hobby is obviously a fairly geeky thing to do. The real core thing that people believe in is free knowledge. So people can copy or modify it, redistribute it."
Wikipedia began when Wales failed in an attempt to create an online encyclopedia because he said he couldn't get enough volunteers. He turned to Larry Sanger who had a breakthrough insight.
"The idea was that anyone could go to this Web site and just by clicking a button start working on an article," he said. "All barriers to contribution were torn down.
Ward Cunningham provided the tools and invented a program to collaborate on the Internet quickly. In fact, Wiki is Hawaiian for quick.
"Wiki Wiki Web is what I called it," he said. "People who don't even know each other can find the way to fit their thoughts together."
It's that sharing of ideas that's at the heart of Wikipedia. It turns out that people like Adam Krellenstein like to share what they know and are eager to volunteer their time.
"I don't think of it as work. I think of it as play," he said.
"It just is a fun thing to do," Wales said. "It's very entertaining to enter into a dialogue with other people. And you can start on the article and come back a week later and find it to be three or four times as large. So someone saw your article and decided to add to it."
It's not as if encyclopedias are anything new. This first edition of "Encyclopedia Britannica" was printed back in 1768 in Edinburgh, Scotland. "Britannica" is not just in books anymore; it's also online, with animation, graphics and videos. But its executive editor, Theodore Pappas, is not enthusiastic about a free Wikipedia.
"Excellence does not come cheap," he said. "And the last time we checked, hiring the foremost minds in the world, Nobel Prize winners, scientists, they do still like to eat. And they still like to get paid."
Most encyclopedias rely on paid experts to write articles that are checked and re-checked.
"We take fact checking extremely seriously," Pappas said.
Wikipedia says it takes fact-checking seriously, too, but since it only has volunteers and a shoestring budget funded by donations, everything about it is radically different.
"On Wiki you start with publication and that's when you start your review," Cunningham said. "I mean it sounds backwards cause you might publish mistakes."