Yahoo said Wednesday it will anonymize most of the data it collects about people's Web searches after three months, a move that could put further pressure on competitors Google and Microsoft to do the same due to privacy concerns.
Yahoo, which previously kept the data for 13 months, will now retain it for the least amount of time compared to its rivals.
Google said in September that it would anonymize data after nine months, down from 18 months. Microsoft keeps data for 18 months, although it said earlier this month it would reduce the period to six months if its rivals did the same.
A European Union group has recommended that search engines discard data after six months. The recommendation has been endorsed by data protection officials from the 27 countries in the European Union. Countries could eventually choose to enforce the recommendation, which will be discussed further next year.
Privacy campaigners have expressed concerns that Web users could potentially be identified on the basis of search terms and other data. An IP (Internet protocol) address can identify a person's ISP (Internet service provider) as well as their approximate geographic location. It also has been shown that a person can be identified on the basis of search terms they've entered.
Technology companies have maintained they needed to keep the data to observe how people use their search engines in order to improve their search services, such as increasing the relevancy of results.
Yahoo said it would anonymize its "user log data," although the company did not define exactly what data it collects. Other data that will be scrubbed include page views and clicks on ads.
Yahoo said it will keep some data for up to six months for security and fraud reasons, as part of some "specific and limited exceptions," it said in a statement. It may also be required to keep some data longer to meet legal obligations, it said.
Microsoft said on Wednesday it welcomed Yahoo's move. However, the company contends it more thoroughly anonymizes data than either Yahoo or Google, which is more important than how long the data is kept.
Microsoft said it fully anonymizes IP addresses and deletes cookies, which are small data files containing information such as a user's operating system, browser version and a unique identifying number.
Collectively, the information is a more accurate way of identifying a user and could be used to recognize a user even when they are logged in under a different IP address on a different computer, according to E.U.guidelines.
Google maintained its position, saying it will strive for a balance between privacy and the utility of its search engine.
"When we make changes to our policies, they are not conditioned on what our competitors will do," according to a statement attributed to Peter Fleischer, Google's global privacy counsel.