SAN FRANCISCO — Hopping on the privacy-protection bandwagon, Microsoft Corp. and Yahoo Inc. are limiting how long their Internet search engines retain potentially sensitive data about their users.
With the safeguards confirmed Monday by Microsoft and Yahoo, all of the Internet's largest search engines have changed the way they handle the personal information collected about the millions of people who use their free services each day.
The search engines all appear interested in staying a step ahead of regulators as the industry mines personal data to customize ads tailored to the tastes and interests of each visitor.
Those efforts have focused attention on the potential for intrusions into people's privacy if the data amassed by search engines is subpoenaed in a legal investigation or stolen by computer hackers.
The more sophisticated data mining also has prompted federal antitrust regulators and lawmakers to take a harder look at Internet search leader Google Inc.'s proposed $3.1-billion acquisition of ad-delivery service DoubleClick Inc.
The search engines compile lists of requests being made by specific users with personal log-ins. But even for users who do not log in, the search engines track the requests based on their computers' Internet addresses.
Microsoft has set an 18-month time limit on keeping personal data. Yahoo will scrub the personal information within 13 months.