How much does Google know?

NEW YORK — Google is at once a powerful search engine and a growing e-mail provider. It runs a blogging service, makes software to speed Web traffic and has ambitions to become a digital library. And it is developing a payments service.

Although many Internet users eagerly await each new technology from Google Inc., its rapid expansion is also prompting concerns that the company may know too much: what you read, where you surf and travel, whom you write.

“This is a lot of personal information in a single basket,” said Chris Hoofnagle, senior counsel with the Electronic Privacy Information Center. “Google is becoming one of the largest privacy risks on the Internet.”

Not that Hoofnagle is suggesting that Google has strayed from its mantra of making money “without doing evil.”

Rather, some privacy advocates worry about the potential: The data’s very existence — conveniently all under a single digital roof — makes Google a prime target for abuse by overzealous law enforcers and criminals alike.

Through hacking or with the assistance of rogue employees, they say, criminals could steal data for blackmail or identity theft. Recent high-profile privacy breaches elsewhere underscore the vulnerability of even those systems where thoughtful security measures are taken.

Law enforcement, meanwhile, could obtain information that later becomes public, in court filings or otherwise, about people who are not even targets of a particular investigation.

Though Google’s privacy protection is generally comparable to — even better than — those at Microsoft Corp., Yahoo Inc., Amazon.com Inc. and a host of other Internet giants, “I don’t think any of the others have the scope of personal information that Google does,” Hoofnagle said.

The concerns reflect Google’s growing heft. As startups get bigger and more powerful, scrutiny often follows.

Google says it takes privacy seriously.

“In general, as a company, we look at privacy from design all the way (through) launch,” said Nicole Wong, an associate general counsel at Google.

That means product managers, engineers and executives — not just lawyers — consider the privacy implications as new technologies are developed and new services offered, Wong said.

She also said that Google regularly seeks feedback from civil liberties groups such as the Center for Democracy and Technology and the Electronic Frontier Foundation, both of which credit Google for listening even if it doesn’t always agree.

Google’s privacy statements specify that only some of its employees have access to personal data — on a need-to-know basis — and such access is logged to deter abuse.

Google chief executive Eric Schmidt says a tradeoff exists between privacy and functionality, and the company believes in making fully optional — and seeking permission beforehand — any services that require personally identifiable information.

“There are always options to not use that set of technology and remain anonymous,” Schmidt told reporters in May.

Here’s just some of the ways Google can collect data on its users:

• One of Gmail’s selling points is its ability to retain e-mail messages “forever.”

• Google’s program for scanning library books sometimes requires usernames to protect copyrights.

• The company is testing software for making Web pages load more quickly; the application routes all Web requests through its servers.

• Google also provides driving directions, photo sharing and instant messaging, and it is developing a payments service that critics say could add billing information to user profiles.

Because storage is cheap, data from these services can be retained practically forever, and Google won’t specify how long it keeps such information.

Without elaborating, Google says it “may share” data across such services as e-mail and search. It also provides information to outside parties serving as Google’s agents — though they must first agree to uphold Google’s privacy policies.

Much of the concern, though, stems from a fear of the unknown.

“Everybody gets worried about what they (Google) could do but what they have done to date has not seemed to violate any privacy that anyone has documented,” said Danny Sullivan, editor of the online newsletter Search Engine Watch.

Anne Rubin, 20, a New York University junior who uses Google’s search, Gmail and Blogger services, says quality overrides any privacy concerns, and she doesn’t mind that profiles are built on her in order to make the ads she sees more relevant.

“I see it as a tradeoff. They give services for free,” she said. “I have a vague assumption that things I do (online) aren’t entirely private. It doesn’t faze me.”