Mozilla has announced that the Associated Press has become the first organization to adopt the "Do Not Track" http header introduced by Firefox 4.

According to a blog post from Mozilla privacy man Alex Fowler, the AP News Registry is now using the header across 800 news sites reaching 175 million unique users a month.

He also says that the Digital Advertising Alliance (DAA) – an collection of big name media and advertising agencies that seeks to self regulate the behavior advertising biz – is "initiating a process to explore" the use of Mozilla's Do Not Track header.

Mozilla proposed the header with a January blog post, hoping to give netizens the option of shielding themselves from ad networks that attempt to track their web behavior, and the idea was soon rolled into Firefox, which made its official debut in March. Within the browser, users have the option of turning on the Do Not Track header, and then it's up to websites and ad networks to actually recognize it.

In a December report on web privacy, the Federal Trade Commission recommended a "simple, easy to use choice mechanism for consumers to opt out of the collection of information about their Internet behavior for targeted ads". The most practical method, it said, would "involve the placement of a persistent setting, similar to a cookie, on the consumer’s browser signaling the consumer’s choices about being tracked and receiving targeted ads".

Following Mozilla's Do Not Track proposal, the FTC recommended melding the DNT header with advertising industry efforts to self regulate. This seemed to spark movement from the DAA. "The leaders of the five groups that make up the DAA approved moving forward with determining how to include the header into its existing program," Fowler said. "As a result, Mozilla is beginning an effort to collaborate with the DAA and other stakeholders to explore both business and technical requirements to further support broad implementation of the DNT header."

To turn on the header within Firefox 4, check the “Do Not Track” box in the “Advanced” screen of the Firefox “Options” interface on a PC or the “Preferences” interface on a Mac. ®