Administrators have TOTAL control over the board, their job is to make sure everything runs smoothly and make the board look good. And choose the moderators, helpers, and Advertisers.
Moderators are hand picked by the Admins and their job is to keep a watch over the forum and they also have the power to ban people.
Helpers are people picked to report posts that are against the rules, they are - as the title states- helpers to the mods and admins, they make their job a little easier.
Advertisers are pretty much self explainitory, their job is to advertise and get people into the forum by any means neccesary, such as Posting on other sites, advertising on maplestory and even by requesting to affiliate with another site and then alerting an admin to the affiliate if accepted.