Following through on my articles on tanking, today I will talk about threat, what it is, how to get it, how not to lose it and what to do when you do lose it. First let's define what threat is. In short, threat is the amount of hate you have on a given enemy or more commonly referred to as "mob". As a tank, your job is to lead your group through an instance and absorb all the damage and minimize the amount of damage your group receives as much as possible, in order for you to accomplish this, you need to generate enough threat so that mobs hate you more than the rest of your party.
There are several tools at our disposal that enable us to do this, but be mindful of the fact that you can't do it alone, how often I've seen DPS and even healers in a group grab aggro before I have even gotten into position, i.e. as I run into a pack of mobs a healer throws a heal over time on me just as I'm in aggro range, and ooops! there goes a stray mob onto my healer... or an overzealous DPS caring only about being #1 on the damage meters who can't wait a second or 2 to allow me to grab my pack of mobs throw an ability on them before laying into them with their damage... and OH! there goes a dps!
Thankfully we have tools in order to help in this situation, and those tools are our Taunts. We have 2 taunts as Paladins plus a couple of other nifty abilities we can use to help on top of the taunts but we will cover those later. For right now, let's take a closer look at how threat works, the math behind it.
A good post over at Maintankadin's lays out the mechanics very well, so I don't feel the need to re-write this part, so here's a copy / paste of the part of that thread that applies to this post.
"Each mob has a counter for every player how much threat that person has. This starts out at 0 usually, unless there's some specific mechanic; there might be a very small amount of proximity threat for pulling a mob; but I didn't check.
As players perform actions that generate threat this 'threat' counter of that mob for that person rises.
Dealing damage to the mob usually causes the threat counter of the mob for the damage dealing player to increase by 1 per point of damage dealt (threat modifiers apply).
The mob also has a current 'target' which is what it's currently attacking.
If another player has more than 110% of the threat that a mobs target has AND is in melee range the mob will change it's target. If another player has more than 130% of the threat that a mobs target has, even if he is not in melee it will change it's target.
Many threat addons don't show the RAW threat but 'effective' threat and 110/130% will appear as 100%, but this is just so people who don't know how it works can understand it more easily; this will make 'taunt' appear to generate threat but it's actually an illusion, taunt simply sets your threat to the current targets threat and changes the mobs target (and the former target then has to generate 10% more to get from 100 to 110% to steal the mob back)
Nowdays for most skills the threat generated simply has a % modifier; Defensive Stance/Righteous Fury/Frost Presence/Bear Form simply multiply your threat generated by some number, some abilities also get an additional multiplier (the ones with 'causes high amount of threat' in their tooltip).
The threat counter accumulates indefinately until the mob dies. Since the threat counter is independant for each dpser it means that if you have more than one dpser on the mob you need a smaller threat lead as the mob will live less before it dies. (You only fight the highest dpser for threat, all the others are basically 'free')
When you decide if you can leave the target you should think about how long you expect it to live vs. how long you expect a dpser to catch up to you. More dpsers on a mob will make this easier, since time to live will go down but they won't catch up any faster. Individual good dpsers have no effect on this, as both time to live aswell as time to catch up goes down.
IIRC Heals generate half the amount healed in threat divided evenly on all mobs currently in combat with the healer. So a healer healing the tank for 25k greater heal will generate 12k threat on 1 mob, or ~4k on 3."
Ok so now that we've covered how threat works we can talk more about taunts. Taunt brings up your threat on your target to the same amount of threat it's target has, in other words if say for example you're in a fight requiring that 2 tanks taunt off each other (example coming to mind is Saurfang, or Festergut , Lady Deathwhisper etc. ) your taunt will put your threat level at the same as it's previous target (the other tank) and you will have 3 seconds to get at and past 110% (for melee, and 130% for ranged) of that threat level to retain aggro, otherwise it will revert back to it's previous target. This is a "fixate" that lasts 3 seconds and is basically built into the taunt ability.
We have 2 effective taunts, the first being our single target taunt "Hand of Reckoning", and we also have "Righteous Defense" which taunt's up to 3 enemies forcing them to attack you.
"But Eridian!!!??? How do we use these spells effectively?" Simple my friend, you don't use them when you don't need to use them. In other words, don't throw Hand of Reckoning into your rotation while tanking, it's not necessary as it won't increase the amount of threat you have and it does no damage as your target is already targetting you, so not only do you lose the added benefit of the damage it does, but you just put 1/2 your taunts on cooldown... Brilliant! so if you lose threat to your healer and you're not quick enough to hit your Righteous Defense your healer is now dead. Got it? good. Don't use it to pull either. Save it for that moment in the pull when you know your DPS is pre-mature (ahem) and bursts AoE just as you've body pulled (i.e. generated proximity threat only) that's when you want both your taunts available in most cases. Other than that, you will be using them only if you lost aggro on a given mob, or a group of mobs, and if you're running with a group that knows what the hell they're doing, you will never have to use your taunts at all. Too often group members think aggro is the tanks job only, whereas it's everyone's responsibility to understand and manage. You do your part and they do theirs, and everything should work as intended.
Now. If all hell breaks loose and you lose total control and your taunts both end up on cooldown, what to do... what to do... I'll tell you what to do, throw a Hand of Protection on whoever the hell just pulled aggro on your mob. Not only is it funny to know that for a second or 2 that person will be all confused as all of a sudden they're button mashing and nothing is happening until they realize you've put a Hand of Protection on them, but it will also force the mob back onto you (unless someone else is higher on the threat table than you are, but if that's the case then you definitely need to read more than I can share... my advice then is to completely go back to the basics). Next and last is Hand of Salvation, I use this in conjunction with Omen Threat Meter, when I see one of our guild's awesome DPS start to get a little too close to me, I'll put Hand of Salvation on them, it will set them back in threat a bit, giving you just enough breathing room to make sure you don't lose aggro.
This pretty much covers threat, the rest is up to you my friend, but also up to your party or raid group, don't be shy to tell them if they're not giving you enough time to get into position before nuking the crap out of your mobs, or worse yet, if you see an arrow whizzing by your ear as your running towards your mob pack feel free to give that huntard an earful or better yet save time and just remove him from the group, if a dps opens up before you've actually done your pull, they're idiots. Plain and simple. For any tank to do a good job, the rest of the team also needs to do a good job, we only shine when our group performs as they're supposed to.
Hope you found this helpful, there will be more about threat covered in Skills and Abilities and our Rotations.
Cheers!