Or it could be completely tailored to a person's preference. Say for instance you want certain actions to create lines to have certain hues of color or turn certain ones completely off. I could see how it could give an advantage to other players, but it's in the game for everybody to use for themselves. So say buffing spells I could see be purple hues if you wanted, red to be npc aggressive actions, green healing, blue attacking, yellow are skills, etc, but let the players themselves decide what they want.