It said the change would make its Bing search a better choice for privacy-conscious users than the world's leading search engine Google Inc, because Microsoft will delete the entire Internet Protocol address from search queries, the string of numbers that shows a computer's location.

"We believe that the balance between privacy and efficiency is very much in the mind of consumers," Microsoft's associate general counsel John Vassallo told reporters. "Getting the balance right does make the search engine more attractive." Microsoft says its search engine has some 2 per cent of the European market, well below Google on 80 per cent.

Google says keeping data from search queries is important to improving the way it processes search results and "represents a crucial arm in our battle to protect the security of our services against hacks and frauds." It says it makes users' search details anonymous after nine months and allows people see and control some of the information that is stored on their searches.

Yahoo says it deletes IP addresses and makes user log data anonymous after 90 days, with some exceptions to fight fraud, secure systems and meet legal obligations. EU data protection officials have questioned the need for search engines to keep data on searches and had asked for a six-month limit.