Many of the country's largest companies lashed out at Microsoft this week, claiming that its decision to turn on the "Do Not Track" privacy feature in Internet Explorer 10 would "harm consumers, hurt competition, and undermine American innovation."

In a letter addressed to three top Microsoft executives, including CEO Steve Ballmer and the company's top lawyer, Brad Smith, companies ranging from McDonalds and General Motors to Intel and Visa demanded a sit-down with Microsoft to discuss Internet Explorer 10 (IE10).

IE10 is slated to ship alongside the Windows 8 operating system on Oct. 26. Although Microsoft has promised to also release a version of the browser suitable for Windows 7, it has consistently refused to give a timetable.

"ANA's Board of Directors is very upset that the choice being made by Microsoft is one that will ultimately threaten to reduce the vast array of free content and services available to consumers," the advertisers claimed. The Association of National Advertisers (ANA) is an industry lobbying group.

Microsoft drew the ire of online advertisers -- and praise from many privacy advocates -- when in late May it announced that IE10 would have the "Do Not Track" (DNT) option switched on by default. Later, it backed away slightly, saying users could turn it off when they were first told of the feature as Windows went through its setup paces.

Do Not Track is a browser feature that signals whether a user wants online advertisers and websites to track his or her movements. Four of the five major browsers -- Firefox, Internet Explorer, Opera and Safari -- can send a DNT signal. Google has pledged that Chrome will support DNT by year's end.

"When presented as a default 'on,' by design Microsoft is no longer creating a choice of whether or not data about consumers will be tracked," the ANA's letter continued. "Rather, Microsoft appears determined to stop the collection of Web viewing data. That is unacceptable."

The letter was the harshest criticism yet by the advertising industry of Do Not Track in general and Microsoft's position with IE10 specifically. The ANA used phrases like "fundamentally bad for consumers," "undermines consumer interest" and "cheat society" in its missive.

Essentially, the ANA argued that if advertisers could not track users on the Web -- and then use that information to deliver targeted online ads to them -- the Internet as it's now known would vanish. IE10's on-by-default stance threatened that tracking.

"Microsoft's decision to block collection and use of information by default will significantly reduce the diversity of Internet offerings and potentially cheat society of the robust offerings that are currently available," the ANA said.

Privacy proponents hit back.

"The online advertising industry has dropped its facade of negotiating Do Not Track in good faith," said Jonathan Mayer, one of two Stanford researchers who devised the HTTP header concept used by browsers to signal a user's DNT decision. "This week's letters to Microsoft and W3C leadership are part of that."

The Worldwide Web Consortium (W3C) is a standards-setting group that is trying to finalize DNT's implementation. The group is meeting this week in Amsterdam to continue discussions. Mayer is active in the W3C discussions.