The European Union has sent letters to internet giants Google, Microsoft and Yahoo, warning them that their search engine privacy policies are not compliant with European law.
Under European law, search engines are supposed to delete any user data they have collected after every six months.
Google, Microsoft and Yahoo currently retain user data for a much longer period.
EU representatives said Microsoft's Bing search engine retained data for six months and kept user IDs in the form of cookies for 18 months, whereas Google kept user data in its search engine for a period of nine months.
Yahoo, on the other hand, anonymises user information after 90 days but does it by removing last two digits from the user's IP address.
In the letters sent to Google and Yahoo, Jacob Kohnstamm, chairman of the EU's Working Party 29 (WP29) Data Protection Commission wrote: “On behalf of the data protection authorities in the EU united in WP29, I call on you to improve the protection of the online privacy of users of your search engine services.”