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What kind of phone/device do you have? This seems like something that could potentially be part of a manufacturer's UI (TouchWiz, Sense, Motoblur, etc). – eldarerathis♦May 6 '11 at 13:38
Green: Available. You are online and ready to chat.
Yellow: Idle. Your status automatically changes to idle when
you're away from your computer for 15
minutes. You can't manually select to
appear idle
Red: Busy. This lets your contacts know you're busy and don't want to be
interrupted
Grey: Signed out of chat, or Invisible. If you set your status to
Invisible, you'll appear to be signed
out of chat even when you're actually
signed in.