A useful feature would be marking my character that I am AFK. When another player asks me to join a group or whispers to me, they would receive a notice, preferably with a message option.
Example command:
/afk back in five
If no message is given, there would of course be a default.
May want to also consider a graphic over the players head so other players can see instantly. There must also be an option for the AFK to remain in that state while the player is active. I'm often AFK while crafting. Perhaps it would remain until the player specifically turns it off.
