The worst part about the DNT header was the requirement for the tracking companies to regulate themselves. Initially, the header was opt-in, but with the introduction of IE10, Microsoft decided that the option was going to be opt-out. Once the the DNT header was gaining traction and a not-so-small percentage of people began sending the header, the companies had no reason to comply, and the initiative sorta fell out o…
Call me a conspiracy theorist, but being a former CTO of an adserving company, I feel qualified to at least voice my opinion: this was a brilliant move by Microsoft. The DNT header as it were, was a perfect middle-ground for advertising companies: people that cared enough were able to opt-out, and people that did not care would still be able to be tracked.
Google had the most to lose. I feel Microsoft made this decision in order to (accelerate the) kill of the DNT header, and thus hoping on more severe legislation.