NEW YORK — Google Inc., expanding its efforts at providing software that helps users create and post their own materials on the Internet, has acquired a California startup that develops online collaboration tools known as wikis.

The announcement came Tuesday through separate postings at Google's and JotSpot Inc.'s web journals. Terms were not disclosed.

JotSpot chief executive Joe Kraus said JotSpot would be able to tap into the Internet search leader's large user base and robust data centers capable of handling any growth.

"Our vision has always been to take wikis out of the land of the nerds and bring it to the largest possible audience," Kraus said in an interview. "There's no larger audience that you can reach than one you can reach through Google."

Wiki tools, popularized by the online encyclopedia Wikipedia, let users create, modify and even delete information on items that others in a group have produced.

In July, JotSpot released a new version that aims to make shared pages similar to spreadsheets, photo albums and other software people already use. In the past, Wiki tools have generally mimicked basic web pages or word-processing documents -- photographs, for instance, might appear as a list of attachments, with no thumbnails previewing the image before downloading.

Kraus said Google shared his company's vision for helping groups collaborate online. As the two companies talked over the past nine months, he said, "we were completing each other's sentences."

The deal isn't Kraus' first encounter with Google. Long before Google became a household name, co-founders Larry Page and Sergey Brin considered forgoing their own search engine and licensing their technology instead. According to John Battelle's book "The Search," Page unsuccessfully tried to get US$1.6 million from Excite, an early search engine Kraus had co-founded.

Google's acquisition of JotSpot, which closed Monday, comes as the search company prepares to purchase the online video-sharing site YouTube Inc. for $1.65 billion in stock.

Earlier in the year, Google said it bought Upstartle, the maker of the online word-processing program Writely. Google has since packaged Writely with an online spreadsheet it developed in-house. The free tools could help groups simultaneously work on documents over the Web and provide alternatives to Microsoft Corp.'s dominant business-software applications, which largely run on computer desktops rather than the Internet.

Kraus said Google's acquisition of JotSpot "validates the notion that people want to do more online than just read. The web is moving from a monologue to a dialogue."

As JotSpot makes the transition to Google's systems, new registrations have been suspended. Existing users can continue using the service, and JotSpot will stop billing for paid accounts.

Kraus declined to discuss future product plans under Google. In the past, Google turned the Picasa Inc.'s $29 photo organizer into a free download, but it sold a premium version of Google Earth, a mapping product that incorporated technology acquired from Keyhole Corp.

JotSpot currently has 30,000 paid users at about 2,000 companies using a service hosted on premise or at JotSpot. About 10 times as many people use the free, JotSpot-hosted service, which restricts the number of pages and the size of the collaborating group.

Kraus said Google has yet to determine whether existing users would eventually have to sign up for free user IDs through Google, as Writely users ultimately had to do.

The universal identity could heighten privacy concerns, making it easier for governments to obtain one's search history, e-mail messages, word-processing documents and now wiki data with just one subpoena. Kraus said users could delete accounts before migrating to Google.

Shares of Google fell 18 cents to close at $476.39 on the Nasdaq Stock Market.