The struggle to set a standard for a Do Not Track program continues.

Two years into the process, the Tracking Protection Working Group of the World Wide Web Consortium has failed to reach an agreement about how DNT should be defined and exactly what features should be included. The group called a time-out on negotiations last fall after it failed to reach a consensus.

After beginning work again this spring, the working group voted earlier this month on various approaches to a DNT program. The ad industry submitted a proposal – put forth by the Digital Advertising Alliance, the American Association of Advertising Agencies, the Association of National Advertisers, the Network Advertising Initiative, and the Interactive Advertising Bureau, among others – that was voted down.

Under the proposal, companies could continue to send behavioral advertising to consumers, even after they chose DNT, by profiling users and serving targeted ads. The industry argued that some browsers default to DNT, so unless consumers click on an opt-out link in a privacy notice or via the industry’s self-regulatory program, it is unclear whether they have truly chosen not to be reached by advertisers. The groups agreed that certain information – such as the specific URLs of Web sites visited – would be stripped from a user’s profile.

Privacy advocates spoke out against the idea, and the W3C working group rejected the proposal, “finding it at odds with our chartered aims and the weight of group consensus,” cochairs Peter Swire and Mathias Schunter said. The ad group’s suggestion was “less protective of privacy and user choice than earlier initiatives.” Instead, the 110-member group decided to work on a different proposal.

In response, industry members indicated that they are unlikely to support the alternative. Stu Ingis of the DAA told MediaPost he is “not optimistic” that members will follow the W3C’s standard, while Rachel Thomas, vice president of governmental affairs at the DMA, said it’s “unlikely” that the industry would do so. “It looks to me like the W3C has devolved into an academic exercise on this issue,” she said.

Why it matters: While the W3C rejection of the ad industry’s proposal sent a message, it didn’t get the working group closer to a solution. The working group acknowledged that its self-imposed deadline of July 31 to agree on a standard for DNT will not be met. The deadline has been bumped multiple times after an initial due date of January 2012 and is currently 18 months behind schedule – with an uncertain future.