• by Wendy Davis  @wendyndavis, August 20, 2013

Two years ago, ad-serving company TruEffect became one of the first Web companies to say it wouldn't serve targeted ads, or collect campaign measurement data, from people who sent do-not-track requests through their browsers. But on Tuesday, the company announced that it will no longer honor do-not-track settings.

Chief Marketing Officer Tim Mayer says the company changed course after noticing that the proportion of users sending do-not-track signals reached 20% this June, up from 14% in May. He attributes the increase to Microsoft's decision to activate do-not-track by default in the Internet Explorer 10 browser.

“We were seeing a lot more IE 10 browsers, and that was impacting our customers' measurement,” Mayer says. He adds that TruEffect was placing itself at a competitive disadvantage by honoring do-not-track signals, given that most of the industry ignores them.

All of the major browser companies now offer do-not-track headers, which tell publishers and ad networks that users don't want to be tracked. But the header doesn't actually prevent tracking. Instead, ad networks and publishers decide on their own whether to honor the signals.

For the last two years, Web companies, computer scientists and privacy advocates in the World Wide Web Consortium have tried to forge a consensus about how to respond to do-not-track signals. But the group has reached a standstill, with privacy advocates and industry representatives unable to resolve their disagreements.

One of the sticking points centers on how companies should respond when do-not-track is turned on by default, either by a browser company or security software. Some ad companies have said they will only honor settings that are selected by users, but privacy advocates point out that there's no way to know whether a consumer or software provider has configured the browser.

Another point of disagreement involves whether companies should be able to collect analytics data from users who have enabled do-not-track. Privacy advocates say that all data collection should stop, but industry executives say that they are only willing to stop serving targeted ads to people who enable do-not-track.

TruEffect's Mayer says that the company might revisit its decision about do-not-track signals once the industry arrives at a consensus about how to interpret them. “We're waiting for an industry standard,” he says.

He adds that the company intends to roll out a platform to allow its advertiser clients to choose whether or not to honor the settings based on the user's browser.