"Many people don't understand the kind of unnoticed conversations that are going on between them and [Google's servers]," said John Simpson, policy advocate at Consumer Watchdog. "Some of that can provide a useful, helpful service to the user, but people need to know what they're providing and made informed judgments about whether they want to or not."

Search vendors have of late moved in varying degrees to assuage user privacy concerns, albeit not to the degree groups like Consumer Watchdog would prefer.

Yahoo recently said it will anonymize most personal data it collects after three months; in September, Google it would keep such information for nine months, halving its previous policy of 18 months. Microsoft, which now retains the data for 18 months, said recently it would drop that to six months if other search vendors agree.

Consumer Watchdog is targeting Google because the company is such a dominant player in Internet search, Simpson said. "It's really the opportunity for them to become the gold standard for privacy on the Internet. If they can be made to see the light, then others will fall into line too."