Google Inc.'s new tracking tool that keeps a detailed history of a person's web search has raised privacy concerns among experts who complain that information collected can't be permanently deleted by the user.

The Mountain View, Calif.-based search giant launched the "My Search History" feature in beta late Wednesday. In order to use the tool, a person has to first create a Google account with user name and password. The feature is automatically available to people who have already signed up for other features, such as Google web mail.

People using the new tracker can search their own history of web pages found on Google, use a calendar to navigate to any day in their search history, and get additional information from search results, such as when they last viewed a page and how often they've seen it.

A person's personal search history is integrated with Google.com's search results, so the user would be presented with information about what they have already searched for and clicked on.

Google allows people to remove any listing from the history, and to pause the feature at anytime, so searches can't be recorded. The remove feature, however, doesn't go far enough, according to some experts.

While deleted listings can no longer be retrieved from the web, they remain in Google's internal systems.

"As is common practice in the industry, Google maintains a separate logs system for auditing purposes and to help us improve the quality of our services for users," the company says in its privacy policy. "For example, we use this information to audit our ads systems, understand which features are most popular to users, improve the quality of our search results, and help us combat vulnerabilities such as denial of service attacks."

Because the information is not permanently erased, and is associated with a person's user ID and password, it could be useful to law enforcement agencies investigating a criminal case or by lawyers in a civil case, such as a lawsuit, experts say.

"(The information) can be subpoenaed and will be," Pam Dixon, executive director of the World Privacy Forum, said. "This is really problematic."

Alan Eustace, vice president of engineering at Google, acknowledged that handing over personal information to anyone carries risk.

"Anytime, you give up any information to anybody, you give up some privacy," Eustace said.

With "My Search," however, information stored internally with Google is no different than the search data gathered through its Google.com search engine, Eustace said.

"This product itself does not have a significant impact on the information that is available to legitimate law enforcement agencies doing their job," Eustace said.

Nevertheless, the risks outweigh the benefits, Dixon said. Web browsers, such as Microsoft Corp.'s Internet Explorer and Mozilla Foundation's Firefox, already keep a history of the web pages people visit, and while Google's tool may have better capabilities, it also carries higher risks.

"Why do I want to give information to a third party when I don't need to?" Dixon said. "It doesn't make good sense."

Eustace, however, disagreed, saying, "For most users, they would rather have access to their (search) history."

People who do a lot of research, such as analysts and journalists, may trade the risk for the benefits of the tool, Charlene Li, analyst for market researcher Forrester Research, said.

"(But) for many people, it's not going to be worth it," Li said. "I don't expect the average (Internet) user to use this."

Google rivals Yahoo Inc., Ask Jeeves Inc. and A9.com, which is owned by Amazon.com Inc., also have similar capabilities in accessing search history.

Among the benefits Google gets from the tool is more information about an individual's web searching, which could eventually help in providing results more relevant to that person, Li said. For example, someone who has searched for information on Hawaii, and later searches for cruise vacations, could be given results about Hawaiian cruises.

Nevertheless, what can be discovered about people through the information they seek on the web is better kept private and away from third parties, Dixon said.

"I have nothing to hide, but that doesn't mean I want the world to see (what I do)," Dixon said.