Kind of fascinating that their biggest cost is site moderation! This seems... odd for a site whose main mechanic really isn't social networking.
Also, we're a chess website with more than one million games per day, and some people like to cheat. We're classifying "fair play and anti-cheating" as "moderation" in our expenses because the two are intertwined.
EDIT: I ask because I was once accused of smurfing (I'm only a casual player) in the chat during the endgame.
Sandbagging is related: deliberately losing to play people with lower ratings.