Microsoft will eliminate all data collected on Bing users after six months. The software giant said it sent a letter to the Article 29 Data Protection Working Party, a collection of the EU's top minds on data protection and privacy issues, today notifying it that the company would reduce the amount of time it stores IP addresses from searchers from 18 months to six months before deleting them.

Currently, Bing takes search data and separates the user's account information (such as e-mail or phone number) from the non-personal information (such as what the query was) and only after 18 months does Microsoft take the additional step of deleting the IP address and any other cross session IDs associated with the query. The only difference with the new policy is that the IP address will be removed completely at six months to provide greater user privacy protection; the rest of the process will remain the same, since Microsoft says it needs the data to make search better for consumers.

The change will be implemented over the next 12 to 18 months. The aim is to satisfy the European advisory group, which has been critical of how search engines collect and retain data on individuals for advertising purposes. In April 2008, the group issued a major report in which it said search engines can only hang on to European user data for six months, must generally treat IP addresses as "personal information," and must comply with the rules even if they are based outside the EU. The panel, which is comprised of national privacy regulators from each of the 27 countries, asked Google, Yahoo, and Microsoft to comply with these demands. After changes made last year, Google keeps data for nine months while Yahoo is at three months.

The Article 29 group is only an advisory body at the EU level, meaning its members are the national data protection regulators from each EU country, and while it holds the power to fine companies, it has not moved to impose sanctions over the search data retention. Microsoft's announcement today tries to find the balance between studying trends in search queries to improve the quality of results and preserving consumer privacy and is likely to avert future problems in the EU.