"Activates countermeasures, instantly lowering threat by a moderate amount."

What is "threat"?

I'm a pvp-er, is this a pve thing?

Threat is a PVE mechanic which can be summed up as how interested a monster is in someone.

Damage is the simplest way to gain threat, whoever does the most damage to a monster has the highest threat.

The monster attacks that person.

Counter Measures lowers threat to help avoid a dps from being the person that gets attacked if a tank is trying to keep the attention of a monster.

Thanks for clearing that up for me.

I'm hoping to start doing some pve, so i'll bare that in mind before bursts.

Threat is a PVE mechanic which can be summed up as how interested a monster is in someone.

 

Damage is the simplest way to gain threat, whoever does the most damage to a monster has the highest threat.

 

The monster attacks that person.

 

Counter Measures lowers threat to help avoid a dps from being the person that gets attacked if a tank is trying to keep the attention of a monster.

Not really... damaging abilities generate 1 threat per damage, so a 5k damage hit will generate 5k threat. The simplest way to gain threat is to use high threat generating abilities, which are reserved to tank classes, because those deal more than 1 threat per 1 damage. Also other abilities like force pull generate 8k threat without dealing damage. Also taunts will bring the taunter on top of the threat table regardless of other people's threat

Not really... damaging abilities generate 1 threat per damage, so a 5k damage hit will generate 5k threat. The simplest way to gain threat is to use high threat generating abilities, which are reserved to tank classes, because those deal more than 1 threat per 1 damage. Also other abilities like force pull generate 8k threat without dealing damage. Also taunts will bring the taunter on top of the threat table regardless of other people's threat

A rather simplified way of putting it. Although there are more numbers to it, which I have conveniently forgotten. It also depends on range. And taunt multiplies the threat already generated by the tank, if you start the fight with taunt, mobs will attack the tank for 6 seconds and then immediately shift focus over to healer/dps simply because 0 damage x taunt multiplier(I think it.s 1.3) = 0 threat generated.

But back to topic, it's basically what everyone's saying. It's an aggro dump, that's next to useless while levelling to 55(except maybe in FPs). However, once you get into 55 ops, it becomes an ability you use a few GCDs into your opening rotation and every time it's off cool down after that. Not doing so will result in tanks hating you, and healers yelling at you.