The status menu allows you to let other users know if you are available to receive messages. Please note that messages will still appear on your screen even if you are in Away/DND mode.
The available status options are:
Online: You are at your computer and available to receive messages.
Away: You are temporarily away from your computer.
DND: (Do Not Disturb) You are at your computer but do not want any messages sent to you.
Invisible: You will be able to see who is online, but they will not know you are online.
Offline: You will be disconnected. You won't be able to see who is online, and nobody will be able to see you.