I just had a quick look onto it myself and can official say its a complete joke of a ranking system.

Apparently some of my friends from the news industry (where I used to work), being minor local celebs/TV personalities... with thousands of follows they interact with daily... friends with proper international celebs... are scoring lower than some of my friends that just rant bullocks.

I wouldn't bother about this service being very indicative of anything in the real world.