Behind the scenes in the escalating war between ad-blocking consumers and advertisers and ad-supported publishers, the use of one privacy tool has decreased. Mobile marketing platform firm Tune reports that, as the number of ad-blocker downloads rises, the limit-ad-tracking feature available in iOS and Android devices has actually dropped.

Use of the limit-ad-tracking setting fell to 16.7% of devices in February from 22% in August 2015, according to Tune, which observed 1.3 billion mobile app installs by about 150 million people over seven months, from August 2015 to February 2016.

This is the first example of data measuring the use of the limit-ad-tracking feature, said Jules Polonetsky, ‎CEO of the Future of Privacy Forum. Limit ad tracking, he continued, "despite being this central privacy control, really doesn't get a lot of debate or discussion."

"This is actually really, really good news, kind of like a second chance," for advertisers, said John Koetsier, mobile economist for Tune.

Apple introduced the limit-ad-tracking function in 2012, and Google followed with a similar feature for Android the following year. "On iOS and Android, enabling the setting does essentially the same thing: limit the amount of information advertisers can legitimately use about your viewing and interaction with ads," notes the new Tune report, "Ads, Tracking and Privacy."

When the feature is enabled, advertisers are only allowed to use limited data for frequency capping of ads and to measure conversion.

In some versions of Android, the feature is not easy to find and could be listed as "interest-based ads" or "Ads based on your interests."

Tune also surveyed around 4,000 smartphone owners and found that the percentage of consumers who think they have the ad-tracking limitation enabled -- 30% -- is higher than the percentage who actually do.

The company said the drop in limit-ad-tracking use is largely the result of a substantial drop in activation of the feature on Android, which was down 36% in the seven months use was observed.

Many people are not aware of the feature, despite the heightened interest in ad blocking and privacy in recent years. "I read privacy policies all the time and I'm always surprised that it's often not referenced in policies," said Mr. Polonetsky.

According to an August 2015 report from PageFair and Adobe, ad blocking in the U.S. rose 48% to 45 million active users in the year leading up to June 2015.

Why are people reducing their use of limit ad tracking? Tune suggests that some are downloading ad blockers in the belief that they will assuage their privacy protection concerns. However, many ad blockers do not function in mobile apps, while the limit-ad-tracking features do.

In addition to a lack of information about the limit-ad-tracking function on iOS and Android, consumers and firms operating in the mobile environment are confused about what data use it actually restricts.

"I've talked to ad networks who say, 'I didn't sign any contract with Apple' or who say, 'I don't know what it means,' " said Mr. Polonetsky. He added he fears that if companies do not take limit ad tracking seriously, they could harm publishers who could get kicked off Google Play or the App Store as a result.

Download the full Tune report here.