The Facebook for Android app has just leapfrogged ahead of Facebook for iPhone in the number of daily active users.
The latest report from Appdata.com shows that the Android app is the more popular mobile Facebook option, making it the first time that has been the case.
To be specific, as of December 2011, Facebook for iPhone has 57.6 million daily active users while Facebook for Android has 58.8 million.
This metric is just the latest in a growing set of statistics that show Android is a more widely used platform than the iPhone.
When it comes to monthly active users, Facebook for iPhone is still the leader, but Android will assumedly catch up on that statistic over time as well.
Comparing numbers like this between the iPhone and Android has always come with a footnote, since Android is available throughout all carriers and on a wide range of devices, while the iPhone is carrier-restricted and only counts a handful of different models.
So it has become pretty black-and-white that Android is the more popular platform, but any one of the iPhones is a much more popular phone.