Google is issuing this warning to people who try to click on links to sites with spyware and other malicious code: "The site you are about to visit may harm your computer!"
Users can search again, learn more about malicious code at the site StopBadware.org or proceed to the suspect site anyhow — at their own risk, of course.
Google Inc. said its initiative is just starting and is by no means comprehensive.
"To begin we'll only be identifying a small number of sites, but we'll be expanding our coverage over time," the company said in a statement. "Finding new and better ways to protect our users is a perpetual project, and we'll continue to work hard in this area."
Google is one of the main sponsors of StopBadware.org, a project that researchers from Harvard and Oxford universities are hoping to turn into a clearinghouse for information on spyware and other malicious software.
So far, StopBadware has identified only one site as malicious, and efforts to reach that site from Google worked normally Wednesday. But Google has identified other sites as problems and is offering warnings for those.
The company said the sites have been identified using software algorithms and verified with outside experts.
In related news, CEO Eric Schmidt said Wednesday that although he was alarmed by AOL's haphazard release of its subscribers' online search requests, the privacy concerns raised by that breach won't change his company's practice of storing the inquiries made by its users.
"We are reasonably satisfied ... that this sort of thing would not happen at Google, although you can never say never," Schmidt said during an appearance at a major search engine conference in San Jose.
The security breakdown, disclosed earlier this week, publicly exposed about 19 million search requests made by more than 658,000 AOL subscribers during the three months ended in May. Time Warner Inc.'s AOL intended to release the data exclusively to researchers, but the information somehow surfaced on the Internet and was widely copied.
The lapse provided a glaring example of how the information that people enter into search engines can provide a window into their embarrassing — or even potentially incriminating — wishes and desires. The search requests leaked by AOL included inquiries seeking information about murder techniques and nude teenage girls.
AOL's gaffe hits close to home for Google because the two companies have extremely close business ties.
Mountain View-based Google owns a 5 percent stake in AOL, which also accounted for about $330 million of the search engine's revenue during the first half of this year. AOL also depends on Google's algorithms for its search results.
Schmidt told reporters Wednesday he hadn't had time to contact AOL executives to discuss the problems underlying the release of the search data, but questioned his business partner's judgment.
"It's a terrible thing," he said during his conference remarks. "Maybe it wasn't a good idea to release it in the first place."
AOL already has publicly apologized for its handling of the search requests, calling it a "screw up."
In response to a reporter's question, Schmidt said some good could still emerge from AOL's error by raising public awareness about the issue. "It may be positive because we want people to know what can happen" to online search requests, Schmidt said.
Google keeps its users' search requests as part of its efforts to better understand what specific people are looking for on the Internet.
But by storing the search requests, Google and its competitors are creating an opportunity for the material to be mistakenly released or stolen, according to privacy advocates.
Schmidt said he is less concerned about those possibilities than the governments of countries around the world demanding to review people's search requests. "I have always worried the query stream is a fertile ground for governments to snoop on the people."
The U.S. Justice Department last year subpoenaed Google for millions of its users' search requests as part of a court case involving protections against online child pornography.
Google refused to comply, resulting in a high-profile court battle earlier this year that culminated in a federal judge ruling that the search engine didn't have to hand over individual search requests to the government.