We believe the header-based approach has the potential to be better for the Web in the long run because it is a clearer and more universal opt-out mechanism than cookies or blacklists.
global privacy and public policy Leader Mozilla Corp.
In a blog post, Alex Fowler, global privacy and public policy Leader at Mozilla, wrote that the Do Not Track HTTP header proposal is the best way to provide people additional privacy when visiting websites.
"We believe the header-based approach has the potential to be better for the Web in the long run because it is a clearer and more universal opt-out mechanism than cookies or blacklists," Fowler wrote.
The proposed browser preference comes with one caveat: In order to fully work, it requires websites to support the feature in the HTTP header. Mozilla issued the browser add-on Universal Behavioral Advertising Opt-out as a proof of concept demo.
Fowler wrote that the header technique is less complex to use and more persistent than cookie-based privacy solutions and "it doesn't rely on user's finding and loading lists of ad networks and advertisers to work," he wrote. With nearly 100 behavioral advertising companies, opting out of each one is too difficult for users.
In addition, Fowler said Mozilla is working to standardize the header-based privacy feature across the industry. "We ask that sites and advertisers join with us to recognize this new header and honor people's privacy choices just as they are with opt-outs for [online behavioral advertising]," he wrote.
Users can currently block tracking cookies in browsers, but it can cause some websites to malfunction and some online advertising networks have found other ways to track visits. A 2009 online browsing privacy study, conducted by researchers at Worcester Polytechnic Institute (WPI) and AT&T Labs Inc., highlighted a method by which third-party advertisers could couple a person's identity with the cookies in their browser by using data provided by social networking websites, such as Twitter, Facebook and LinkedIn.
Privacy advocates have also been pushing for more ways to block advertising networks and search engines from tracking a person's browsing session. The issue has caught the ear of the Federal Trade Commission, which has called for a new mechanism to enable users to opt out of online behavioral advertising.
For example, a Firefox add-on called GoogleSharing.net can be used to prevent search engine giant Google from tracking searches and websites a person visits.