• by Wendy Davis , Today

California Governor Gavin Newsom on Wednesday signed a bill requiring browser developers to offer a tool to enable consumers to easily opt out of online behavioral advertising throughout the web.

Major ad industry groups opposed the bill, arguing it isn't necessary because consumers currently can access opt-out tools through a variety of mechanisms.

But watchdogs like the Electronic Privacy Information Center praised Newsom's move, calling it "a significant step forward for privacy."

AB 566, which was passed last month, specifically prohibits businesses from “developing or maintaining” a web browser that lacks an opt-out preference signal that sends opt-out requests to every site consumers visit.

The best known opt-out preference signal is the Global Privacy Control -- a mechanism created by privacy advocates that essentially sends opt-out signals to every site people visit.

Only some developers -- including Mozilla, Brave and DuckDuckGo -- have built the Global Privacy Control into their browsers. The tool is also available as a browser extension.

Late last month, the Association of National Advertisers, American Association of Advertising Agencies, American Advertising Federation and Digital Advertising Alliance urged Newsom to veto the bill, arguing it imposes "a broad mandate without delivering meaningful consumer benefits."

California law gives residents the right to opt out of behavioral advertising, but privacy advocates argue it's cumbersome to do so without access to a tool like the Global Privacy Control.

“It is far too difficult for most people to use their existing privacy rights,” Matt Schwartz, policy analyst at Consumer Reports, which supports the bill, stated after it was passed.

“AB 566 will change that by requiring browser vendors to provide a clear and easy-to-use setting that allows consumers to universally opt-out, preventing their information from being sold or shared with hundreds of third-parties that they have never even heard of," he added.

Absent a browser-based command, consumers who want to reject behaviorally-targeted ads can click on web companies' opt-out links one-by-one, or can use a tool created by an ad industry group. The ad industry tool allows people to opt out of multiple companies that belong to industry organizations.

In addition to arguing the bill isn't needed, the ad groups that sought a veto said the measure is inconsistent with California's privacy law. The groups contend that the text of the statute actually allows companies to either offer opt-out links on their sites or honor opt-out preference signals.

Regulations by the California Privacy Protection Agency require companies to honor opt-out preference signals, but the ad groups argue that those regulations are based on a misinterpretation of the law's text.