For people tracking the rise and fall of applications on Facebook, a new option is now available: AppData, an analytics site created by Justin Smith, a product manager at app company Watercooler and founder of the blog InsideFacebook. It makes basic data publicly available, including daily changes in application traffic. Facebook itself now only displays the number of monthly active users an app has.

AppData takes the monthly active user data that Facebook makes publicly available, Smith says and organizes it into leaderboard charts and historical graphs

Daily changes in MAU are calculated by comparing today’s MAU numbers with yesterday’s MAU numbers.  While this is not equivalent to calculating the number of new users for an application on any given day, it is a good way to understand which applications are getting more or less popular during the last month.

As for the competition the new service will be facing: Adonomics was an early and well known Facebook app analytics service. It recently got bought by social network advertising company Adknowledge. Like Sometrics and Social Media’s Appsaholic, Adonomics will get reoriented around social network advertising analytics. Meanwhile, rivals like Developer Analytics and Kontagent provide additional services to help developers more comprehensively measure detailed user behavior patterns.