We're changing how we report public app usage metrics to provide a more consistent view of the ecosystem and highlight successful apps earlier in their lifecycle.
We're moving from reporting approximate active user numbers to reporting an overall rank and active user thresholds. For example, an app with 1,100,000 monthly active users (MAU) will now be shown as the #300 largest app by MAU and as having more than 1,000,000 MAU. This reporting change does not alter the actual number of people using apps, and developers continue to have access to their exact usage metrics in App Insights.
On January 16, 2013, our APIs and all areas on Facebook.com will reflect these changes. To provide access to the new ranking data, we're adding the "daily_active_users_rank" and "monthly_active_users_rank" fields to the application object via the Graph API and FQL.
We hope the new ranking data helps people identify fast-growing web and mobile apps that use Facebook.
The following stats are for activity between 01/02/2013 - 01/09/2013: