As the online search giant Google Inc. prepares to change the way it uses information about Internet users, regulators and consumer watchdogs worry that the company will compromise the privacy of millions of consumers.
On March 1, Google will alter the way it uses data it collects on Internet users to build more detailed individual profiles of many consumers.
The changes will affect only users who are signed in to a Google account, but that includes millions of consumers who use Google services such as Gmail, the video site YouTube, or smartphones running the company’s Android operating system.
Consumer and privacy advocates fear that Google already collects too much personal information about too many individual Internet users.
Some consumers are uncomfortable with the idea their buying habits and other interests can be used to profile them for advertisers. Others worry that information, once amassed, could be vulnerable to theft and public distribution beyond their control.
An Annenberg Foundation study published in 2010 found that such concerns span all age groups, including those who grew up in the Facebook era, with personal information being widely, and often publicly, shared online.
Already, Google has a sometimes uncanny ability to place online ads related to the personal interests of Internet users on sites they view, thanks to a treasure trove of data it collects from visitors to its own Web pages. That potentially includes such information as where else they go on the Internet, what devices they use, and their location.
For instance, when people log into Google’s video service YouTube, the company keeps track of what videos they view. But now, that information is not being shared with other Google services such as the company’s Web search.
Under the new policy, all information about any user signed into any Google account will be combined in a single database. Google, which makes money by selling and placing online ads, said it will be able to deliver more accurate search results and advertising that is more relevant to individual customers. And its ability to speak to individual interests and habits will become even more precise.
That would also boost Google’s advertising business by helping to target users with the ads most likely to interest them. Companies would probably buy more ads on Google’s various sites, and pay more for them, if the company can promise that it is reaching more interested buyers.
Google stressed that it will not collect any more user information than it already does and has promised it will not sell personal information to advertisers. Through a “dashboard’’ service that lets users see the information Google has collected about them, an individual can delete some of this information or completely delete his Google account.
In addition, many Google services, such as its Internet search or YouTube, can be used without signing up for a Google account, which means the company will not be able to identify visitors to those sites.
Some critics said that simply changing the policy breaks a 2011 consent agreement between Google and the Federal Trade Commission imposed after allegations that Google violated its users’ privacy.
Last month, Markey and Representative Joe Barton of Texas, his Republican counterpart on the privacy caucus, asked the FTC to investigate whether the policy violates the agreement. And earlier this month, the Electronic Privacy Information Center, an Internet civil liberties group in Washington, sued the FTC, demanding that it take action to block the new Google policy.
Dan Jacobs, consumer privacy fellow at the center, said Google’s policy shift is unfair because many users signed up for specific Google services in the belief that any collected data would be kept separate from other information collected by the company. Now Google is changing that policy, without giving customers the right to opt out.
“They want to change the rules without coming back to me and getting my consent,’’ said Jacobs.
Users can opt out of the new policy, but it means taking drastic action - abandoning their Google accounts, or deleting the stored information. In their letter to the company, Coakley and the attorneys general noted that this would be disruptive for millions of consumers as well as for many businesses and government agencies that have come to rely on Google services.
People who use Android smartphones, for example - nearly half the smartphone users in the United States - may sign up for a Google account.
These phones often share a variety of personal information with Google, ranging from the names in their phone directories to copies of the photos they take with the device’s built-in camera.
Google’s efforts to collect more information about its users have frequently gotten the company into hot water.
For instance, The Wall Street Journal reported last week that the company bypassed a security setting on Apple Inc.’s Safari Internet browser. This let Google see the Web surfing activities of Safari users who had believed their activities were not being tracked. Google has said that the tracking was due to a technical error and has been halted.
And in 2010, the company came under fire from privacy regulators worldwide, when it admitted it had intercepted private wireless Internet traffic.
Despite those incidents, Google has not experienced any large backlash from consumers, possibly because the popularity of its services outweighs privacy concerns.
On Wednesday, the Obama administration announced its support for an Internet privacy bill of rights, based on standards to be drawn up by major Internet companies such as Google, Microsoft Corp., and Facebook Inc.
The proposal would ensure that consumers get access to the information collected by Internet firms, give them the right to set limits on how companies use the data, and allow them to demand that the information be deleted.
And yesterday, Google, Microsoft, Yahoo Inc., and an organization of major online advertisers agreed to adopt “do not track’’ technology for Net browsers.
Hiawatha Bray can be reached at email@example.com.
Clarification: a previous version of this article imprecisely described how Android smartphones operate. Users without Google accounts can perform basic functions such as making phone calls and sending text messages but cannot use some advanced features of the phone.