They're all staff, so why the different coloured names?
Purple = Administrators ; Site owners, here to help with whatever you need!
Blue = Global Moderators; Here, there and everywhere! These guys are watching over the whole forum.
Green = Moderators ; Here to help you out in the roleplay and social sections, respectively.
And here they are in name and title:
Username Title Short Review Meow-nificant Mod Roleplay Moderator The Prettiest Princess Roleplay Moderator