Seven months after Google began testing a service called Knol, a Wikipedia competitor, the company on Wednesday finally introduced it.

The search expert Danny Sullivan aptly describes Knol as “Like Wikipedia, With Moderation.” Articles on various topics are penned by individuals, and in many cases, experts — not collectively by the anonymous masses. Knol authors can choose to benefit from the “wisdom of the crowds” by letting others edit or supplement their articles. But those changes make it into Knol entries only with the author’s permission.

Knol, which, by the way, is short for knowledge, is making some people uneasy because it further transforms Google from a search engine that helps people find content into a site that helps people create and publish content.

Even though it will make money on many Knol pages with its AdSense program, Google promises that the objectivity of its search engine will not be compromised.

“We will treat Knol pages as we treat other Web pages,” said Cedric Dupont, a Google product manager. “If there is a Knol that is the first place in search results, it deserves that place.”

Of course, on many searches, it is Wikipedia’s ad-free pages that show up at the top of search results.

Mr. Dupont dismissed speculation that Knol was designed as a Wikipedia killer: “Google is very happy with Wikipedia being so successful. Anyone who tries to kill them would hurt us.”

There is a striking similarity between one aspect of the two sites. The text of Knol articles uses the same font as Wikipedia. Mr. Dupont said that is simply coincidence, as it is a commonly used font.

For now, Knol has only a few hundred articles, compared to the nearly 2.5 million in Wikipedia’s English language version. And for now, the best place to follow the debate on whether or not Knol is a Wikipedia killer is on the Knol entry on, where else, Wikipedia.