Some privacy advocates have expressed concern that users will not be able to "opt out" of the new policy, which will allow advertisers to develop personalised messages based on Web searches, use of Android mobile devices or activity on other Google products.

But Chavez said that "some important things aren't changing: We're still keeping your private information private -- we're not changing the visibility of any information you have stored with Google."

Additionally, "We're still allowing you to do searches, watch videos on YouTube, get driving directions on Google Maps, and perform other tasks without signing into a Google Account."

He added that Google will continue to offer "privacy tools" including an ad preference manager, and "We still won't sell your personal information to advertisers."

For users who dislike the policy, he noted, "We're still offering data liberation if you'd prefer to close your Google Account and take your data elsewhere."

The change comes nearly a year after Google reached a settlement with the US Federal Trade Commission over privacy concerns with Google Buzz, a social networking tool.

The deal called for audits of Google's privacy efforts.