Search engines should cancel personal information held about their users within six months, a European Committee advisory organic structure on information protection have said.
The recommendation is likely to be accepted by the European Committee and could take to a clang with hunt giants like Google, Yokel and MSN.
Google and Yokel anonymise user information after 18 months, while MSN makes the same after 13 months.
The organic structure said hunt companies were not clear adequate on information protection.
Google said its privateness policy "strikes the right balance" between privacy, security and innovation.
No-one from Yokel or MSN was immediately available for comment.
Peter Fleischer, Google's planetary privateness counsel, said in a statement: "Google takes privateness incredibly seriously; protecting our users' privateness is at the bosom of all our products.
Search engine suppliers must cancel or irreversibly anonymise personal information once they no longer function the specified and legitimate intent they were collected for
Article 29 Working Party report
"It is the ground we were the first company to perpetrate to anonymising our hunt logs, and also why we dramatically shortened our penchant cooky lifetime."
Many hunt engines currently accumulate and shop information from each hunt query, holding information about the hunt question itself, the alone personal computer computer address (known as an information science number), and inside information about how a user do their searches, such as as the web browser that is being used.
Users who make an business relationship with a hunt engine manus over more than information to the firms, including hunt history. Some hunt engines also enrich personal information held on their users with information from 3rd parties.
The study from the Article 29 Data Protection Working Party said hunt engine suppliers had "insufficiently explained" why they were storing and processing personal information to their users.
It said "search engine suppliers must cancel or irreversibly anonymise personal information once they no longer function the specified and legitimate intent they were collected for".
The study said the personal information of users should not be stored or processed "beyond providing hunt results" if the user had not created an business relationship or registered with the hunt engine.
The consultative organic structure also said it preferred hunt engines did not accumulate and usage personal information to function personalised ads unless the user had consented and signed up to the service.
Yokel is one of the world's prima hunt engines
The organic structure was put up to supply expert sentiment to the European Committee and to do recommendations in the countries of personal information and privacy. The Committee usually follows the recommendations the organic structure makes.
The study also said hunt engines did not necessitate to garner further personal data, beyond the information science computer address of a machine being used, in order to present basic hunt consequences and advertisements.
It added: "Because many hunt engine suppliers advert many different intents for the processing, it is not clear to what extent information are reprocessed for another intent that is incompatible with the intent for which they were originally collected."
It said hunt engines should not utilize personally identifiable information to better their services or for accounting purposes.
Personal information stored for security intents should not also be used to better services, the organic structure recommended.
The study issued a set of duties to seek engines firms, including:
Search engines should acquire informed consent from users if they correlative personal information across different services, such as as desktop search
Search engine suppliers must cancel or anonymise (in an irreversible and efficient way) personal information once they are no longer necessary for the intent for which they were collected
Personal information should not be held by hunt engines for longer than six months
In lawsuit hunt engine suppliers reserve personal information longer than six months, they must show comprehensively that it is strictly necessary for the service
It is not necessary to accumulate further personal information from individual users in order to be able to execute the service of delivering hunt consequences and advertisements
If hunt engine suppliers utilize cookies, their lifespan should be no longer than demonstrably necessary
Search engine suppliers must give users clear and intelligible information about their personal identity and location and about the information they mean to accumulate shop or transmit, as well as the intent for which they are collected
The study also warned that if hunt engines enriched personal information about users from 3rd political parties they could be breakage the law unless clients had given expressed consent.
It said users had the right to access, inspect and right all the personal information about themselves held by hunt engines, including their profiles and hunt history.