Congress and the U.S. Federal Trade Commission (FTC) also waded in on IE10 and Do Not Track as the W3C met in Bellevue, Wash., last week to continue hammering out the standard.
Reps. Edward Markey (D-Mass.) and Joe Barton (R-Texas), the co-chairs of the House privacy caucus, sent a letter of their own (download PDF) to the W3C last Tuesday, pressing for a change in its stance on IE10.
"We believe that browsers which default to Do Not Track provide consumers with better control and choice with respect to their personal information," Markey and Barton said. "We call on W3C participants to make the protection of consumer privacy a priority and support Microsoft's announcement by endorsing a default Do Not Track setting."
One of the FTC's commissioners, however, disagreed with the congressmen.
"Microsoft's default DNT setting means Microsoft, not consumers, will be exercising choice as to what signal the browser will send," wrote J. Thomas Rosch in his letter (download PDF) to the W3C on Thursday.
The European Commission's idea that browsers should prompt users for their DNT choice has been considered by at least two browser makers, according to Jonathan Mayer, a researcher at Stanford's Center for Internet and Society (CIS). Mayer is one of two Stanford students who devised the HTTP header concept used by browsers to signal a user's DNT decision.
The W3G's DNT group has discussed the so-called "first-run" option, said Mayer in an interview earlier this month.
That solution is reminiscent of the deal the EU struck with Microsoft in 2009 that required the U.S. developer to show a browser ballot dialog box in Windows to offer Europeans multiple alternatives to IE.
Microsoft must include the ballot in Windows 8 when it launches this fall to give users in the EU a chance to download and install browsers other than IE10.
The European Commission's urging of a first-run DNT prompt could signal that it takes the privacy setting as seriously as browser competition, and that it may push aggressively for the choice dialog.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is gkeizer@computerworld.com.
See more by Gregg Keizer on Computerworld.com.