If you want to know who your most engaged fans (Facebook Page users) are, NapoleonCat comes to the rescue.
All you need to do is connect your Page as a managed profile (here's how to do it) and then visit our Analytics module and go to the "Influencers" tab.
You'll see a list of the 20 most engaged users, which means that these people (or other Facebook Pages) did the following:
commented on your posts,
reacted to your posts (liked etc.),
or published a visitor post on your Page.
Users are ranked by the Activity Index value from top to bottom. The Activity Index is calculated as the sum of all the above interactions performed by the user multiplied by the following weights for each type of interaction:
post = 9,
comment = 3,
like = 1.
For example, if John Doe commented once on one of your posts and liked one of them, his Activity Index will equal (1 x 3 + 1 x 1) = 4.