Google and Microsoft said they currently keep data linking searches to IP addresses for 18 months, while Yahoo said it only keep it for 13 months.

"For me personally, it still seems rather long, and I could imagine I am not alone," Peter Schaar, chairman of the Article 29 Working Party, told The Financial Times, according to MediaPost.

Some U.S. advocates are happy about the news. "The bottom line is that search companies keep information," said executive director of the Electronic Privacy Information Center Marc Rotenberg.

Last month, Rotenberg requested an order asking Google to stop storing IP addresses. "The search engine functionality would not be impaired if a search engine did not store any user information at all," Rotenberg stated.

However, Google and other search companies said they use the IP logs data to improve the search results and to police click fraud.

A Google spokesperson said the company is "committed to collaborating with privacy advocates, consumer protection groups and regulators, including the Article 29 Working Party, to work together to explore ways to improve privacy online for all users,” according to MediaPost.

Google's storage of IP addresses marked one of the reasons why it acquired DoubleClick. The advocates worry that Google will tie its information about users' searches to DoubleClick's information about people's Web-surfing behavior, which can possibly end in extremely detailed profiles.

Later last year, the Federal Trade Commission proposed guidelines for behavioral targeting techniques, which include the recommendation that online users have the opportunity to opt-out of being tracked online via cookies, Media Post reported. The agency Tuesday extended the comment period for those guidelines until April 11.

It is expected that the Interactive Advertising Bureau will release its own suggested guidelines this week.