TauntMaster

TauntMaster is a tanking addon that came out shortly after Patch 3.3. It is a threat management addon that displays a button/healthbar for each party or raid member. These buttons are initially grey, but change color based on the party member's aggro level. The user can then taunt a party member's target off of them by clicking their button.

Color Key

 * Grey: Threat is lower than the tank
 * Yellow: Threat is higher than the tank, but the player is not tanking anything
 * Orange: The player is insecurely tanking
 * Red: The player is securely tanking
 * Blue Border: Indicates the player is a tank
 * Green Border: Indicates the player has a friendly target (its target cannot be taunted)
 * Yellow Border: Indicates the player has the same target as one of the tanks

Preprogrammed Spells

 * All Classes:
 * Ctrl-Click: Assist
 * Death Knight:
 * Left Click: Dark Command
 * Right Click: Death Grip
 * Druid:
 * Left Click: Growl
 * Right Click: Challenging Roar
 * Paladin:
 * Left Click: Hand of Reckoning
 * Right Click: Righteous Defense
 * Ctrl Click: Hand of Protection
 * Warrior:
 * Left Click: Taunt
 * Right Click: Intervene
 * Shift-Left Click: Challenging Shout

Current/Future Versions
The current version is 4.1.1. The add-on is now fully customizable. Different spells can be used and even macros, in place of the pre-programmed abilities. There has not been much word on future releases although the author has hinted at setting an anchor point for the UI. The raid warning feature of TauntMaster also needs to be updated for Cataclysm.