Facing worries about its tracking Web surfers' every move, Google Inc. is now offering a feature to track Web surfers' every move.
Its free Web History service is strictly voluntary — Google users can sign up to have the Internet giant keep detailed records of every website they visit so they can easily find them again later.
The feature is similar to that offered by Web browsers, except the data are stored on Google's servers instead of users' computers and there's no set time after which it is erased.
Web History's quiet debut this week came as privacy advocates continued to raise alarms about the prospect of Google combining its collection of information on individuals with that of DoubleClick Inc. Google has agreed to acquire the New York-based company, which distributes Web ads and tracks where the majority of people go on the Internet, for $3.1 billion.
Three consumer groups filed a complaint over Google's privacy practices with the Federal Trade Commission on Friday, asking it to investigate before approving the DoubleClick deal.
The complaint to the FTC cites a 2006 poll by the Ponemon Institute, a Michigan-based research group that studies privacy issues. When Google users were asked whether they believed that the company captured data that could be used to identify them, 77% said no.
In fact, Google ties search queries to the Internet address associated with a specific computer. The Mountain View, Calif.-based company said last month that it would "anonymize" the data by stripping those addresses from its records after 18 to 24 months.
"Polling information can be persuasive in establishing a reasonable belief that the data aren't identifiable," said privacy attorney Chris Hoofnagle, who worked at the Electronic Privacy Information Center and is now at the Berkeley Center for Law & Technology. "They've got a shot, but it's still a stretch."
In a statement, Google said the electronic privacy group's complaint was "unsupported by the facts and the law." It said that the trust of its users was essential, that its privacy policies were clear and that its users were given choices about what would be done with their information.
Google says the personal data it collects allow it to customize its search and other services, making them more useful for consumers.
Gartner Inc. analyst Allen Weiner agreed that Google users benefited from the practice but said it was a trade-off most people were uncomfortable with. Still, he said, Google continues to push the boundaries because "in order to continue to evolve its product, it truly needs for some of these things to be overcome."
Privacy concerns also have arisen over DoubleClick. A public outcry in 2000 ended the ad company's efforts to use people's names and Internet addresses in tracking online habits. In 2002, it settled lawsuits by state attorneys general and consumers over its privacy practices and promised to tell consumers more about their ability to block tracking software.
Google and DoubleClick took pains this week to explain that because only DoubleClick's advertising clients own the data about where Web surfers go, Google cannot simply merge that information with the profiles it has.
But Richard M. Smith, a privacy and security researcher, said Google could instead give its data to DoubleClick's clients.
"It doesn't matter if it is in one big database," Smith said. "It will go the other way."
DoubleClick referred questions on that theory to Google, which declined to make an executive available for comment.
As for the new Web History offering, Smith notes that Google already collects lists of websites visited when people use its Toolbar and PageRank functions.
Web History, Smith said, "illustrates to people directly how much information Google is capable of collecting."