As the debate continues about a potential privacy system that would allow consumers to opt out of having their data collected online, Microsoft on Tuesday announced a feature for the newest version of Internet Explorer that would permit users to stop certain websites from tracking them.
The feature, which will exist in Internet Explorer 9, available next year, will let users limit the ability of third-party companies to track them online. The announcement comes less than a week after the Federal Trade Commission advocated a "do not track" mechanism that could be built into a browser and alert websites that a user did not want to be monitored.
Jon Leibowitz, the commission's chairman, said in a statement that he was encouraged by Microsoft's move.
"Microsoft deserves enormous credit for taking a critical step toward providing consumers with more choice about who can track their online browsing," Mr. Leibowitz said. "Just as important, this announcement proves that technology is available to let consumers control tracking."
A blog post issued by Microsoft said the company was applying the principles outlined in the FTC's report, including the idea that companies should build privacy features into their products.
The new feature, called Tracking Protection, would rely on lists that users create that indicate which sites they do not want to share information with. Lists can be created by individuals or by organizations, like consumer advocacy groups, which can make their lists available for anyone to use.
Once enabled, the tracking protection would exist for all Web pages the user visits and would take effect each time they start a new browsing session. The mechanism would identify and block third parties from collecting data through cookies and other mechanisms that track users.
Jules Polonetsky, the co-chairman and director of the Future of Privacy Forum, said users would most likely decide to use lists published by Web sites they trusted instead of creating their own, adding that most people would likely ignore the option all together.
"The average user is not going to have a list of 500 ad networks and 600 analytics companies," Mr. Polonetsky said. "They end up relying on a privacy watch dog to give them a do-not-track list that the browser will respect."
Microsoft's announcement comes at a time when some in the online advertising community fear that a government-mandated do-not-track system could have severe ramifications for their business models. Rik van der Kooi, the corporate vice president of the advertiser and publisher solutions group at Microsoft, said in a statement that the new privacy tools could co-exist with the growth of online advertising.