I would like to know who are my most active Facebook friends, over time. That is, who among my friends submitted the most stuff (statuses, links, images, etc.) during some significant period of time (say, 3 months).
Skyttle Friends allows you ... to monitor your Facebook presence, ... get insights into your fans' discussions, behaviour and ... activities
Hope this helps
I would also suggest you TopFan app (rating of the most active followers of Facebook pages) ->> http://applodis.com/apps/topfan
Application for determination of the most active page and group subscribers on Facebook. Rating is based on likes, comments and shares that fans do on community pages per month, year or a chosen period. Top fan benefits: - increased activity and, consequently, the number of active subscribers; - opportunity to brand applications; - fine tuning and blacklist availability; - daily rankings update.