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Firefox will fight back against intrusive advertisers

The new version of Firefox paves the way for faster, safer browsing and strips websites of ad technology used to follow user behavior.

Firefox SVP Mark Mayo Stephen Shankland/CNET

PARIS -- With its Firefox Web browser, Mozilla plans to take a significant step in the fight against intrusive online advertising.

Firefox for years has had a "private browsing" mode that keeps no record of which websites you've visited. When Firefox 42 arrives on November 3, that mode will add a tracking protection option designed to block advertising technologies that record people's online activity.

"When a user goes into private browsing mode, it's an unambiguous signal for us to put the shields up," said Mark Mayo, Mozilla's senior vice president of Firefox, in an interview Tuesday at Mozilla's offices.

That means people won't see the same ad following them around different websites, some ads will disappear altogether and analytics services won't work for websites trying to understand the demographics of their readers.

Mozilla worked for years to try to coax the advertising industry into embracing a technology called Do Not Track that performed a similar role, but advertising industry representatives objected and the effort faltered. With the new move, Firefox is taking unilateral action, albeit only in the limited private-browsing domain.

Tracking protection, along with the ad-blocking technology that arrived in Apple's iOS 9 operating system that powers iPhones and iPads, reflect a strong push against an ad industry that's being taken to task for ads that can be annoying, invade privacy, slow website loading and drain smartphone batteries. Even the Interactive Advertising Bureau, a consortium of online advertising companies, is trying to cope with an industry that's gone overboard.

Modern ad technology "steamrolled the users, depleted their devices, and tried their patience," said Scott Cunningham, the IAB's senior vice president of technology in an October 15 blog post. He called for ads that were less burdensome and non-invasive. "The consumer is demanding these actions, challenging us to do better, and we must respond."

Firefox enables the tracking protection feature by default, but it only works in the private browsing mode.
Firefox enables the tracking protection feature by default, but it only works in the private browsing mode. Screenshot by Stephen Shankland/CNET

Reclaiming Firefox relevance

With the rise of Google's Chrome and the arrival of smartphones and tablets where Firefox is almost unknown, Mozilla faces a serious challenge remaining relevant in the browser market. As a fraction of worldwide browser usage on PCs and mobile devices, Firefox usage dropped from 12.4 percent a year ago to 9.8 percent now, according to analytics firm StatCounter.

Firefox embodies Mozilla's mission to give people control over their online lives, for example by trying to protecting their privacy and by promoting open Web standards that aren't under the control of any one company. That principled stance hasn't always resonated with the average person who just wants a website to load fast, but it's possible keeping intrusive ad technology at bay could be a feature more people care about.

Firefox users, testing the tracking protection since its arrival in the Firefox 42 beta in September, like the feature, Mayo said. It's not clear yet whether the technology will be added to Firefox's regular browsing mode, but Mozilla will monitor feedback. "It wouldn't be there if we didn't have a large number of users asking us for help in this space," he added.

Firefox's share of global browser usage is steadily slipping while Google Chrome increases. StatCounter

Foundation for new improvements

The new Firefox version also brings a new technology for customizing Firefox with add-ons, an important step in a longer-term plan to improve Firefox safety and performance. That plan, called Electrolysis, will split Firefox into multiple pieces running in parallel, an approach already built into Google Chrome, Apple Safari and Microsoft Edge. That splits off some tasks from the central part of the Firefox software, freeing it for faster performance. And it lets Mozilla confine websites into their own memory compartments, called sandboxes, so it's harder for malicious websites to attack the rest of a computer.

But the new Electrolysis design is incompatible with today's add-ons, which let people customize the browser to block ads, manage passwords, translate text and more. Mozilla is building a replacement called Web Extensions, Mayo said. The new technology mirrors an add-on approach Google pioneered with Chrome, easing the transition for developers who must rebuild their add-ons.

The pain is worth it for enabling Electrolysis, though, Mayo said: "We believe it's where the core architecture needs to go."