Damage Control site moderator and general "YES!" man. Or maybe "Nancy-boy" is a more apt term.
In any case, a guild moderator is more like a senior guild member with extra privileges on the website so the site maintainer & admins can slack off OR blame someone in case the site goes to hell.
Patsies are FTW.
In reality, their job is to assist with recruitment evaluations, guild banking, forum moderation, raid loot updates, guild applications, scheduling, leading raids, drama management... basically whatever they're told to do.