Do-not-track legislation is unnecessary because current industry's self-regulatory program already calls for ad networks to allow users to opt out of online tracking, a coalition of ad and business groups told the Federal Trade Commission on Friday. "Industry currently provides the type of uniform consumer choice for online behavioral advertising that the FTC endorses," the groups said in written comments. "The federal government should not undercut the industry's commitment to the program by creating a duplicative Do-Not-Track mechanism." The comments were filed in response to an FTC report issued last December that sought comment on a host of privacy proposals, including whether the government should require Web companies to offer consumers a mechanism to avoid all online tracking by advertisers and their agents. Groups joining in the filing include the American Advertising Federation, American Association of Advertising Agencies, Association of National Advertisers, Direct Marketing Association, Interactive Advertising Bureau, Performance Marketing Association and U.S. Chamber of Commerce. A federally mandated do-not-track program "would reverse the substantial progress made in the last 15 months and could signal to consumers that they should not trust the business community or online behavioral advertising as a whole," the groups say. The ad organizations also refer extensively to a new self-regulatory initiative that involves placing icons in all ads served based on tracking data. The icons, licensed by the umbrella group Digital Advertising Alliance, take users to sites where they can opt out of online tracking by 60 networks. "Dozens" more ad networks are expected to soon join the program, the groups said. Overall, however, around 300 ad networks are estimated to collect data that is used for online behavioral targeting. Almost 300 comments were filed with the FTC in advance of Friday's deadline. One filing -- by a broad coalition of privacy and child welfare advocates, including The Center for Digital Democracy, American Academy of Child and Adolescent Psychiatry, American Academy of Pediatrics, Public Health Institute and World Privacy Forum -- focused specifically on online marketing to teens. Those groups urged the FTC to say that teens should not be tracked online without their explicit consent. "New media plays an inescapable role in the lives of adolescents," the associations say. "At the same time, adolescents have unique vulnerabilities that can be exploited in the social and online context."