Mozilla turned the blocking of third-party tracking cookies on by default this week with the release of Firefox 69. Although the feature has been available since October’s Firefox 63, this week’s build is the first to enable the feature by default, even for existing users who are just upgrading.
Tracker blocking
Mozilla says that it’s not trying to block actual ads, only trackers. For the most part, it has succeeded; in our testing, we frequently saw 30 or more tracking elements blocked on sites whose ads still display.
