New Fantagian is a rank. There are different ranks for people with a number of posts. For example, a junior fantagian is a person with 50-99 posts, a fantagian is someone with 100-249 posts.
Moderators are the forum's staff. They moderate the forum and their ranks are given by the administrator of the forum, Mace.
Posting a lot doesn't make you become an administrator but it does changes your rank. If you would like more information on the ranks click www.fantageforum.com/t3-posting-ranks