SAN FRANCISCO (Reuters) - Web search leader Google Inc.'s commitment to consumer privacy came under fire from Privacy International, a British activist group that has previously singled out Google for criticism.

The London-based group released a report on Saturday entitled "A Race to the Bottom - Privacy Ranking of Internet Service Companies" that rates Google, alone among 20 sites, as having an "entrenched hostility to privacy."

With each search on Google, the company gathers information about a customer's tastes, interests and beliefs that could potentially be used by third parties such as advertisers. But the company says it never passes on personal data.

While the preliminary report details a handful of specific concerns, the main threat Privacy International spells out is Google's growing size and scope as the world's largest provider of Web searches, along with the consumer data that the company collects as it delivers ever more personalized Web services.

"This is in part due to the diversity and specificity of Google's product range and the ability of the company to share extracted data between these tools, and in part it is due to Google's market dominance and the sheer size of its user base," the report finds.

The rankings were arrived at after a six-month probe of privacy practices at key Web search companies, e-mail providers, and e-commerce and social networking sites. Privacy International promised to issue a fuller report in September, after further consultation with the companies involved.

Google said the latest report was mistaken.

"We are disappointed with Privacy International's report which is based on numerous inaccuracies and misunderstandings about our services," Nicole Wong, associate general counsel at Mountain View, California-based Google said in a statement.

"(Google) stand(s) by our record for protecting user privacy and offering products that are transparent about what information is collected and empower users to control their personal information," she said.

POOR HISTORY

The substance of the accusations against Google are that the company's privacy policy disclosures are incomplete and "possibly deceptive" and that Google has a poor history of responding to consumer complaints. Also it occasionally does not accept public input before introducing services.

"Throughout our research we have found numerous deficiencies and hostilities in Google's approach to privacy that go well beyond those of other organizations," the report states.

"While a number of companies share some of these negative elements, none comes close to achieving status as an endemic threat to privacy," the report says in reference to Google.

But none of the score of sites studied gets a complete clean bill of health.

Facebook and Hi5, two social networking Web sites, were rated as "substantial threats" to consumer privacy for alleged poor handling of consumer personal information.

Similarly low-rated are Apple Inc. and AOL LLC, which are criticized for failing to do more, given their size.

Microsoft Corp. is criticized for "serious lapses," not so much for recent products as for its "terrible" prior track record.

Other Internet properties fare better as "generally privacy aware but in need of improvement." These include BBC.com, auction site eBay Inc. and online music site Last.fm, which is to be acquired by CBS Corp.

In 2004, Privacy International called on European Union regulators to set limits on Google's free e-mail service, Gmail, which targets relevant advertising at users based on a machine reading of the contents of a consumer's e-mail.