ranger4life wrote:
Blue: 7+ lvls lower
Green: 4-6 lvls lower
White: 3 lvls lower to at your level
Orange: 1-4 lvls higher
Red: 5+ lvls higher
Corrected it a bit, although I'm not sure if Red mobs start at 5 lvls higher or 4.
To add onto what ranger said, colors are pretty much a way to show which mobs are around your level and whether or not they're higher/lower (this was more useful before mobs had levels right next to their name).