SAN FRANCISCO — Google Inc. is working on a new Internet encyclopedia that will consist of material submitted by people who want to be identified as experts and possibly profit from their knowledge.
The concept, outlined late Thursday in a posting on Google's Web site, poses a potential challenge to the nonprofit Wikipedia, which has drawn upon the collective wisdom of unpaid, anonymous contributors to emerge as a widely used reference tool.
Google is calling its alternative "knol," the Mountain View, Calif.-based company's shorthand for a "unit of knowledge."
For now, submissions are by invitation only as Google fine tunes the system, but the Internet search leader said it will eventually publish articles by all comers.
"There are millions of people who possess useful knowledge that they would love to share, and there are billions of people who can benefit from it," Ubi Manber, Google's vice president of engineering, wrote in the company's posting about the new service. "We believe that many do not share that knowledge today simply because it is not easy enough to do that."
Since it was founded on the same knowledge-sharing premise six years ago, Wikipedia has compiled 2.1 million English-language articles as well as millions more in dozens of other languages. The topics cover everything from Albert Einstein's theory of relativity to video games like "Beavis and Butt-head in Virtual Stupidity."
Wikipedia attracted 56.1 million U.S. visitors in October, making it the eighth most popular Web site, according to comScore Media Metrix. Google's properties, which include video-sharing site YouTube, drew 131.6 million U.S. visitors, second only to Yahoo Inc.
In a Friday interview, Wikipedia founder Jimmy Wales downplayed Google's latest move. "Google does a lot of cool stuff, but a lot of that cool stuff doesn't work out so great," he said.
Google's flops include a service that used to hire researchers to track down hard-to-find answers for befuddled Web surfers. The feature never took off, prompting Google to pull the plug last year.
While Google tinkers with its encyclopedia, Wales already is poised to invade Google's turf with a Wikia search engine scheduled to debut later this month. The search engine will be operated by Wikia Inc., Wales' for-profit venture.
The Googlepedia, as some observers are already calling the new offering, will differ from Wikipedia by identifying who wrote each article and striving to reward the authors by giving them a chance to make money from Google's lucrative advertising network.
Critics say Wikipedia's cloak of anonymity has made its articles more vulnerable to mischief and other abuses.
Citizendium, an Internet encyclopedia launched earlier this year, also insists on identifying the writers of its articles. But, unlike Google, Citizendium relies on a collaborative editing process to verify the accuracy of its articles.
"Google will not serve as an editor in any way, and will not bless any content," Manber wrote. "All editorial responsibilities and control will rest with the authors."
Google is hoping to keep the contributors honest by allowing visitors to rate the entries and leave comments.
That won't be enough, predicted Larry Sanger, Citizendium's editor-in-chief who also helped start Wikipedia.
"Knol is apt to produce precisely the same sort of uneven content, with many of the same abuses, that Wikipedia has," Sanger wrote in a posting on Citizendium's site.
Google, which is expected to earn more than $4 billion this year, also wants to make money off its encyclopedia. Although the resource will be available for free just like Google's search engine, the company wants to place ads related to the topics covered on each page.
Google is trying to persuade the writers to participate by guaranteeing they will receive a "substantial" share of the revenue.
The profit incentive could turn Google's encyclopedia into a magnet for articles about highly commercial subjects instead of more academic topics, Wales predicted. "You may see an awful lot of articles about Viagra."