Within the space of just 10 months, Microsoft appears to have achieved the exact opposite of what it wanted for Internet Explorer 10, which launches in a default "do not track" (DNT) position intended to shield users from the advertisers that track them.

The major ad lobby groups said yesterday they would ignore Microsoft's DNT signal on the grounds that it represents Microsoft's choice for the browser rather than the affirmative choice of the user. That leaves Internet Explorer 10 as the one browser you should never use if you actually don't want to be tracked.

Worse, it allows Google (Chrome), Mozilla (Firefox), and Apple (Safari) to now remind users that their privacy and anti-tracking controls — which users must opt into — are the only ones now respected by advertisers who use tracking cookies to target ads at users.

It's a stunning reversal.

Microsoft was hoping to launch IE10 with the bold — and highly appealing — promise that this was the one browser on the market designed specifically to shield the privacy of its users. In other browsers, a majority of users either don't want, or fail to adjust, their preferences to block cookies and stop tracking.

Unfortunately, the company failed to get the buy-in of its own clients, who were blindsided and angered by the move. Microsoft then ignored their angry protests, even though the remonstrations included top-level executives like WPP Group CEO Martin Sorrell, who controls billions in web ad spending on behalf of his ad agencies' clients. Advertisers are happy to ignore consumers who choose privacy; but they don't want Microsoft to make that choice for them.

Now, because IE10's DNT signal is merely a signal — not an actual blocking mechanism — that asks advertisers to honor it; and because advertisers have now explicitly stated they will not honor it, IE10 is the one browser that offers users the least amount of privacy from advertisers.

Users seeking privacy should use older versions of IE or Chrome, Firefox and Safari, and should adjust the tools, options, and preferences in favor of private browsing, cookie blocking, and anti-tracking.

Microsoft's only hope is for the FTC to promulgate a rule requiring all browsers to launch in a default DNT position. But even if that happened, IE10 would be only exactly the same as its competing browsers — robbing Microsoft of the positioning it sought when it made its DNT decision at the beginning of the year.

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