AMMAS is short for
Actual
Memeber
Minus
Affiliates
Score

In short, it's a ranking metric that scores organizations based how many actual members it has versus affiliates. The higher the score, the more actual members opposed to affiliates. The lower the score, the more affiliates opposed to actual members.

LindyNet

Redditor LindyNet is the inspiration of this site. LindyNet's StarCitizen Org statistics were a fun way to keep interest in the game while we wait, but also a tool for large organizations to be able to see how well they were doing in comparison to others. The details that LindyNet went into went above and beyond what you would find on the Robert Space Industries site and for that, we salute you sir.