THE campaign to defang the “Do Not Track” movement began late last month.

Do Not Track mechanisms are features on browsers — like Mozilla’s Firefox — that give consumers the option of sending out digital signals asking companies to stop collecting information about their online activities for purposes of targeted advertising.

First came a stern letter from nine members of the House of Representatives to the Federal Trade Commission, questioning its involvement with an international group called the World Wide Web Consortium, or W3C, which is trying to work out global standards for the don’t-track-me features. The legislators said they were concerned that these options for consumers might restrict “the flow of data at the heart of the Internet’s success.”

Next came an incensed open letter from the board of the Association of National Advertisers to Steve Ballmer, the C.E.O. of Microsoft, and two other company officials. Microsoft had committed a grievous infraction, wrote executives from Dell, I.B.M., Intel, Visa, Verizon, Wal-Mart and other major corporations, by making Do Not Track the default option in the company’s forthcoming Internet Explorer 10 browser. If consumers chose to stay with that option, the letter warned, they could prevent companies from collecting data on up to 43 percent of browsers used by Americans.

“Microsoft’s action is wrong. The entire media ecosystem has condemned this action,” the letter said. “In the face of this opposition and the reality of the harm that your actions could create, it is time to realign with the broader business community by providing choice through a default of ‘off’ on your browser’s ‘do not track’ setting.”