What Changed
Mozilla had introduced Enhanced Tracking Protection in 2018 as an option. In June 2019, with Firefox 67.0.1, it became the default for new users.1,2 In its Standard setting, Firefox blocks known third-party tracking cookies, based on a list of trackers maintained by Disconnect, a privacy company.2 Mozilla said this made it harder for more than a thousand companies to follow people across the web, and a shield icon in the address bar let users see which companies were blocked on a page and turn blocking off for a site.1
Existing users received the same default over the following months: Firefox 69, released on September 3, 2019, turned it on for everyone and added cryptomining scripts to the default block list.3,4 Firefox 70, in October 2019, made social media trackers part of the standard protection, blocking the cross-site tracking cookies of sites like Facebook, Twitter and LinkedIn.5 In January 2020, Firefox 72 added known fingerprinting scripts.6 Users could turn it off for specific sites, or choose a stricter setting.
Why It Mattered
With Safari's Intelligent Tracking Prevention already in place, Enhanced Tracking Protection meant two major browsers limited cross-site tracking out of the box. It showed that default tracker blocking wasn't only an Apple position.
Firefox took a different approach from Safari. Rather than classifying trackers on the device with machine learning, it used a published list of known tracking domains. That made its behaviour more predictable, but also meant trackers not on the list weren't blocked.
For advertisers, Firefox's share of browsing was much smaller than Chrome's or Safari's, so the direct effect on reach was limited. It still is: about 6% of desktop browsing worldwide and in Canada in September 2026, according to Statcounter.7,8 Seven months later, Google announced its own plan to phase out third-party cookies in Chrome. Mozilla went further in 2022 with Total Cookie Protection, giving every site its own cookie jar.
Notes
- Dave Camp, “Firefox Now Available with Enhanced Tracking Protection by Default,” The Mozilla Blog, June 4, 2019, https://blog.mozilla.org/en/firefox/firefox-now-available-with-enhanced-tracking-protection-by-default/. ab
- “Firefox 67.0.1 Release Notes,” Mozilla, June 4, 2019, https://www.mozilla.org/en-US/firefox/67.0.1/releasenotes/. ab
- Gregg Keizer, “Mozilla Makes Anti-Tracking the Firefox Default,” Computerworld, June 6, 2019, https://www.computerworld.com/article/1668513/mozilla-makes-anti-tracking-the-firefox-default.html. ↩
- Paul Thurrott, “Firefox 69 Arrives with Enhanced Tracking Protection on by Default,” Thurrott.com, September 3, 2019, https://www.thurrott.com/cloud/web-browsers/mozilla-firefox/214051/firefox-69-arrives-with-enhanced-tracking-protection-on-by-default. ↩
- “Firefox 70.0 Release Notes,” Mozilla, October 22, 2019, https://www.firefox.com/en-US/firefox/70.0/releasenotes/. ↩
- Ionut Arghire, “Firefox 72 Blocks Fingerprinting Scripts by Default,” SecurityWeek, January 8, 2020, https://www.securityweek.com/firefox-72-blocks-fingerprinting-scripts-default/. ↩
- “Desktop Browser Market Share Worldwide,” Statcounter Global Stats, accessed October 11, 2026, https://gs.statcounter.com/browser-market-share/desktop/worldwide. September 2026 figures. ↩
- “Desktop Browser Market Share in Canada,” Statcounter Global Stats, accessed October 19, 2026, https://gs.statcounter.com/browser-market-share/desktop/canada. ↩