600 million Mozilla add-ons downloaded to date

Mozilla Blog of Metrics announced some interesting numbers about Firefox add-ons server by Mozilla Add-ons:

• 4000 extensions available.
• Between 800,000 and 1 million downloads per day.
• About 4.5 million page views per day.
• About 100 million checks for updates occur every day, which represents the minimum number of add-ons currently in use. 96% of these come from Firefox installations.
• More than 600 million add-ons (themes + extensions) have been downloaded (obviously not counting updates).

Based on update ping logs, about 96% of Firefox users are on the 2.0 branch, 2% on 1.x and 1% have already made the jump to the latest and greatest and for-testers-only-yet 3.0 branch. The number could not reflect the complete picture however, as a user that has installed add-ons is probably more likely to have his software up to date but still a pretty high number for any software.

We’ll see how the new Firefox 3 Add-ons Manager boosts add-ons usage and customization.