By Brendan Sasso - 04/24/13 10:45 PM EDT
Many ad networks install tracking files called "cookies" to monitor users' browsing history and display targeted ads to them.
At a White House event in early 2012, a coalition of Internet companies said they would work together to voluntarily implement a Do Not Track option for users. But more than a year of talks between advertisers, browser makers and other Internet companies has failed to produce an agreement.
Lou Mastria of the Digital Advertising Alliance said his industry is still committed to finding an agreement and blamed Microsoft and Mozilla for derailing the negotiations.
Microsoft made Do Not Track the default setting on its Internet Explorer browser last year and Mozilla announced plans earlier this year to block all third-party cookies on its Firefox browser.
Mastria said those actions violate the principles agreed to at the White House last year and threaten to disrupt the "online experience."
He argued that consumers often prefer tailored advertising and that tracking is critical for supporting free online services.
Rockefeller expressed little faith in the voluntary industry negotiations which are currently taking place through the World Wide Web Consortium (W3C).
"His standards are totally unenforceable, and he knows it," Rockefeller said, referring to Mastria.
Rockefeller also argued that the advertising industry's existing "Ad Choices" program is ineffective at empowering users to guard their privacy.
Sen. Richard Blumenthal (D-Conn.) agreed that if industry cannot reach an agreement, Congress should act.
But Sens. John Thune (R-S.D.), Dean Heller (R-Nev.) and Claire McCaskill (D-Mo.) expressed more concern about potentially harming Internet businesses with invasive new regulations.
"It is also important to understand that any solution that blocks third party advertising companies from placing cookies on the Internet will have economic consequences," Heller said. "This sector provides many jobs and generates multiple billions of dollars in economic activity."