Google has announced a service designed to compete with Wikipedia, aiming to create an authoritative repository on every kind of topic.

The company is inviting experts to offer pages detailing topics on which they hold expert knowledge. Google won't edit pages, but will provide tools and infrastructure for the project in a similar fashion to those provided by Wikipedia.

The service is called the Knol project. Announcing it, Google's Udi Manber observed: "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. We believe that many do not share that knowledge today simply because it is not easy enough to do that. The challenge posed to us by Larry, Sergey and Eric was to find a way to help people share their knowledge. This is our main goal."

Knol is still in development and has entered its first phase of testing. Use is presently by invitation only.

"The key idea behind the Knol project is to highlight authors. Books have authors' names right on the cover, news articles have bylines, scientific articles always have authors - but somehow the web evolved without a strong standard to keep authors' names highlighted," Google explains.

A knol on a particular topic is meant to be the first thing someone who searches for this topic for the first time will want to read. The goal is for knols to cover all topics, from scientific concepts, to medical information, from geographical and historical, to entertainment, from product information, to how-to-fix-it instructions.

Once Knol emerges from testing, the company promises that anyone will be free to write a page, noting that competing knols on the same topic are likely to appear, and observing that users will be able to submit comments, questions, edits, additional content, and more.

"At the discretion of the author, a knol may include ads. If an author chooses to include ads, Google will provide the author with substantial revenue share from the proceeds of those ads," the company explains.

"We do not want to build a walled garden of content; we want to disseminate it as widely as possible. Google will not ask for any exclusivity on any of this content and will make that content available to any other search engine."

The project emerges as online users begin to question some of Wikipedia's editorial policies, with some submitters claiming problems persuading the service to accept some historical records.