• by Wendy Davis , Staff Writer @wendyndavis, March 15, 2011

Microsoft has added another privacy feature to Internet Explorer 9: A do-not-track header.

The tool tells the Web sites that consumers visit that they wish to avoid online tracking. It marks the second new browser-based privacy feature in IE9; the first, unveiled last month, allows users to create "tracking protection lists," which allow users to block networks from serving ads on sites they don't own. Mozilla also offers a do-not-track header, meaning that two of the four major browser developers recently created features that allow users to avoid online behavioral advertising.

But unlike some other privacy controls -- like Microsoft's tracking protection lists, or users' ability to simply delete cookies -- the do-not-track header will only be effective if Web companies honor it.

Despite the momentum toward a browser-based no-track tool, industry groups haven't been supportive so far -- at least not publicly. Association of National Advertisers President and CEO Bob Liodice went so far as to complain that praise for the tools from the Federal Trade Commission could dim industry enthusiasm for self-regulatory initiatives. "As our associations and technology partners have strived to sign up participants for our self-regulatory program, more than a few have said, 'Why do I need to bother, if it's going to be built into the browsers?'" he said in a statement issued at the American Association of Advertising Agencies' recent annual conference.

Despite the ad industry's apparent instinct for wariness here, it's inevitable that at least some consumers will deploy the IE9 or Firefox do-not-track header. Any decision not to honor such headers will almost surely fuel calls for new laws, not to mention Federal Trade Commission enforcement actions.

Meantime, laws that encourage companies to allow consumers to opt out of online ad tracking could be on the horizon sooner than people think. Christopher Wolf, co-chair of the Future of Privacy Forum, reports that Larry Strickling, assistant secretary in the U.S. Department of Commerce, will tell the Senate Commerce Committee tomorrow that the Obama Administration supports baseline privacy legislation. "The legislative concept supported by the Obama Administration would have the Commerce Department working with stakeholders to develop Codes of Conduct enforceable by the Federal Trade Commission, that would also create a 'Safe Harbor' (the contours of which are unspecified)," Wolf writes.