What is Cooldown Used (CDUsed)?
It's an addon that monitors many spell casts from your party/raid members (mostly, special spells with long cooldown), like Shield Wall, Rebirth, Guardian Spirit...
Everytime such a spell is used by a party/raid member, it's displayed in many ways on your screen (or chat channels).
You can choose for each spell category (Aura gained, Aura lost, cooldown used, Interrupt used, ...) many display options such in floating combat text, chat channel (party/raid/custom channel), or simply in the special CDUsed window.
You can add custom spells (not monitored by default) to any category, make templates of monitored spells, or use the default templates (tank, heal, kicker, everything).
The addon also tracks tank taunts (miss/success), and kickers interrupts (miss/success).
This addon can be very helpful for raid leaders who want to track who used there survival cooldowns at a critical time, who didn't and caused a wipe.
It can also be very useful for healers to easily see if the tank is under a survival cooldown, and for tanks to see if another tank failed to taunt a boss (miss, immune).
The addon supports plugins which can be added to do special things when a spell is used.
A small plugin named "kick" is installed by default, when enabled, it monitors all party/raid members that are able to use an interrupt spell, and if said spell is in cooldown or not (showing a small progression bar for all player's kick spell).
You can choose to enable or disable the addon on some locations (world, wintergrasp, 5-man instance, raid, battleground, arena) from the configuration menu.
While in-game, use "/cu" to show the CDUsed window. Right click on the window's title to open the configuration menu.
You can resize the window by dragging the bottom right corner of the window.
Hope this addon helps.