The revamped Add-ons Manager in Firefox 4 provides a rich experience for add-on discovery and management, and to power that service Mozilla receives aggregate data on add-on usage. We previously estimated that at least a third of Firefox users had chosen to install an add-on, but knew the number was higher than that.
We’re very excited to report that 85% of Firefox 4 users have chosen to install an add-on — that’s more than 60 million users every day! This number doesn’t include Personas, and even excludes popular add-ons bundled with other software that the user hasn’t actively agreed to install.
Firefox 4 desktop add-on usage from March 22 through June 19, 2011, excluding Personas and several commonly-bundled add-ons
When we first saw this number, we expected it to drop as more and more users upgraded to Firefox 4; remarkably, it has stayed between 89% and 85% since launch in March. It’s also interesting to note that on the weekends when Firefox (and Internet) usage slumps, the percentage of users with add-ons increases, indicating those who browse on weekends are more likely to have customized Firefox.
We’ve also learned that on average, users have 5 add-ons installed, with the following distribution:
Firefox 4 desktop add-on distribution from June 19, 2011, excluding Personas and several commonly-bundled add-ons
With more than 2.5 billion downloads and 580 million add-ons in use every day in Firefox 4 alone, there’s no better time to browse our gallery and make Firefox your own.