On the heels of Microsoft’s decision to make Do Not Track the default setting for its forthcoming Internet Explorer 10, both Apple and Google have implemented the option for their browsers.

Apple’s recently released iOS 6 will replace unique device identifiers with a new type of tracking mechanism, the company said. The new mechanism – called “advertising identifiers” – will not be permanent, making it more difficult to transfer personal information. In addition, Apple will offer users a setting choice called “limited ad tracking” that will prohibit advertisers from collecting data used to serve behavioral advertising.

Google announced that it will also offer a Do Not Track setting for the latest iteration of its Chrome browser that was released on Sept. 13. The request header will feature “DNT:1” whenever a user moves to a new Web site. The company said it was fulfilling a promise it made to the White House earlier this year to enact Do Not Track by the end of 2012.

The concept of Do Not Track gained traction in December 2010 when the Federal Trade Commission released its draft privacy report that endorsed the idea. Mozilla was the first to implement the concept into its Firefox browser, followed by Microsoft for its Internet Explorer. Earlier this year Microsoft went one step further, announcing, to the dismay of the online advertising industry, that the next iteration of its browser would make Do Not Track the default setting.

After experiencing a negative reaction both from the industry and some consumer advocates – who noted that the default setting actually inhibited consumer choice – Microsoft said it would offer users two choices. Those who browse with IE 10 may choose “express settings” that will include the Do Not Track default, as well as “customized settings” that will allow users to opt out of Do Not Track.

Why it matters: Privacy advocates hailed the moves by Apple and Google as an increase in consumer protection. However, the fervor for Do Not Track seems to have cooled in recent months, as parties continue to disagree over exactly what the term means. The World Wide Web Consortium has created a working group to attempt to standardize the term, but consensus has yet to be reached on issues like whether Do Not Track means companies should not collect information from consumers at all, or whether it is acceptable to gather data but not display ads based on that information.