Google is developing an online publishing platform where people can write entries on subjects they know, an idea that's close to Wikipedia's user-contributed encyclopedia but with key differences.

The project, which is in an invitation-only beta stage, lets users create clean-looking Web pages with their photo and write entries on, for example, insomnia. Those entries are called "knols" for "unit of knowledge," Google said.

Google wants the knols to develop into a deep repository of knowledge, covering topics such as geography, history and entertainment.

Google's project will have to catch up with Wikipedia, which includes more than 7 million articles in 200 languages. Anonymous users constantly update Wikipedia entries in an ever-growing online encyclopedia that's edited by a network of vetted editors.

But Google asserts that the Web's development so far has neglected the importance of the bylined author.

"We believe that knowing who wrote what will significantly help users make better use of web content," wrote Udi Manber, vice president of engineering, on the official google blog. Google said anyone can write about any topic, and repetition of entries on the same subjects is beneficial. Google will provide the Web hosting space, as well as editing tools.

Contributors can choose whether to let Google place ads on the knols. Google said it will give the contributors a "substantial" portion of the revenue generated by those ads. While Wikipedia lacks ads, keyword advertising has underpinned Google's growth.

Entries can't be edited or revised by other people, in contrast to Wikipedia. However, other readers will be able to rank and review others' entries, which will then be interpreted by Google's search engine when displaying results.

The concept of peer-reviewed information is nothing new and is implemented in different ways on various Web sites. Yahoo, for example, has an "Answers" feature where users can ask questions, and the response is ranked on quality. Also, most blogs have forms where readers can comment on the author's entry.

Despite those other formats, Google probably feels that "a service like Knol might be necessary to stay competitive," wrote Danny Sullivan, editor in chief of Search Engine Land, in a review.