• by Wendy Davis  @wendyndavis, June 12, 2024

The self-regulatory privacy organization Digital Advertising Alliance on Wednesday plans to unveil a downloadable browser extension that will enable people to opt out of receiving behaviorally targeted ads -- meaning ads selected for web users based on their activity across sites or apps.

The tool, which is still undergoing testing, initially will be compatible with the four largest browsers -- Google's Chrome, Mozilla's Firefox, Microsoft's Edge and Apple's Safari. The new mechanism eventually will also give users the choice between rejecting all behavioral targeting, or accepting targeted ads in certain categories -- such as automotive, travel or pets.

The ad industry's current opt-out mechanism, in use since 2010, stores opt-out requests on cookies in people's browsers.

Those cookie-based opt-outs can be problematic for several reasons, including that privacy conscious users sometimes delete cookies. Years ago, the Digital Advertising Alliance sought to address the impermanence of opt-out cookies by launching a downloadable browser plug-in, "Protect My Choices," that regenerated opt-out cookies that had been deleted. That plug-in will no longer be available after the new extension rolls out, according to a spokesperson for the group.

Another pitfall of cookie-based opt-outs is that some browsers -- including Firefox and Safari -- block third-party cookies, including the ad industry's opt-out cookies, unless users change their settings to expressly allow tracking.

Given the limitations of cookie-based controls, privacy advocates have long promoted other types of opt-out mechanisms -- especially browser-based settings like the Global Privacy Control that users can activate by checking a box. The Global Privacy Control, which essentially sends do-not-track signals to every site that users visit, is currently available in Firefox and some other browsers -- but not Chrome or Safari. 

At least six states have recently passed laws or regulations that require companies to honor opt-outs sent through mechanisms comparable to the Global Privacy Control.

Privacy expert Justin Brookman, director of technology policy for advocacy group Consumer Reports, was skeptical of the industry's planned opt-out extension.

“No one is going to use this,” Brookman says, adding that the Digital Advertising Alliance's Protect My Choices extension failed to gain traction.

Google's Chrome web store shows that the Protect My Choices plug-in has just 70,000 users. 

A Digital Advertising Alliance spokesperson says only a "very small fraction" of people who clicked on a cookie-based opt-out "took the additional step" of installing the Protect My Choices extension. 

The spokesperson adds that most browser users are now “very familiar and comfortable with extensions.”

“For people who want to customize their ad experience, it's just as easy to install an extension as go through the old opt-out process,” the spokesperson says.