Google will soon know far more about who you are and what you do on the Web.
The Web giant announced Tuesday it is planning to follow the activities of users across nearly all of its ubiquitous sites, including YouTube, Gmail and its leading search engine.
Google has already been collecting some of this information. But for the first time, it is combining data across its Web sites to stitch together a fuller portrait of users.
Consumers won’t be able to opt out of the changes, which take effect March 1. And experts say the policy shift will invite greater scrutiny from federal regulators of the company’s privacy and competitive practices.
The move will help Google better tailor its ads to people’s tastes. If someone watches an NBA clip online and lives in Washington, the firm could advertise Washington Wizards tickets in that person’s Gmail account.
Consumers could also benefit, the company said. When someone is searching for the word “jaguar,” Google would have a better idea of whether the person was interested in the animal or the car. Or, the firm might suggest e-mailing contacts in New York when it learns you are planning a trip there.
But, say consumer advocates, the new policy may upset people who never expected their information would be shared across so many different Web sites.
A user, for instance, may not want Google to use your social network to alert estranged friends — or your boss — that you are around the corner at a bar...