Facebook said 350 million of its 800 million monthly active users access the service through mobile devices today in an update today to its statistics page. The last time it spoke about this number was back in March, when it said it had 250 million monthly active mobile users.
Our app tracking service AppData does record actives for Facebook’s different smartphone apps. Since Facebook is likely one of the most, if not the most, popular smartphone app in the world excluding China, its growth can be used as a proxy for developers interested in the market size of each platform.
We went through our service AppData to compile the following figures. The iPhone app is adding about 250,000 users per week to reach nearly 90.1 million monthly active users. Growth has slowed in recent weeks in likely anticipation of the iPhone 5, which may make its debut in October.
Facebook for Android is showing five times as high a growth rate as iOS with nearly 1.5 million users becoming monthly active users every single week.