Taunt works in a funny way, it doesn't really have a mag, the "stronger" taunt depends on how much duration is remaining, so enhancing mag and duration are basically the same. However it also depends on how much damage you have done to the target.
Castle posted explaining it a while ago, because he discovered it didn't work the way he thought it did.
I really should do something about this signature.
The only explanation I can think of for this is if Taunt mag decreases over time to zero at durations end which means that mobs would breakfree from your taunt as your mag fell below there threshhold (mag 2 lieut would escape a mag 4 hold in 20 secs based on a 40 sec taunt) if this is the way it works then 3 slotting a 40 sec taunt would net an increase of only 10 secs. Kinda sad when the way it's represented makes you imagine 100% enhancement on a 40 sec taunt = 80 secs.
Well thats my 0.02 inf worth anyway which is probably about what a Taunt SO is worth IMO. 
Not sure what the Dmg done element you mentioned is but it would be interestimg to find out
A very interesting point of contention this, I would also value some clarification.
Praf's comment regarding damage done having an impact is of particular interest as in the last week I have encountered two tanks in the mid 20 to mid 30 range who insisted they had insufficient end to fight and would therefore only be standing and taunting. The level of aggro management imo was very poor from these 'endurance low, damage shy' tanks.
I have considered the new taunt sets as an option on my tank but then dismissed them in case they did not offer as much as the IO slotted taunt tokens, perhaps I should look again.
More info very welcome........
In my detailed info it may say I may say 6.78 taunt for 33,4 secs. This means squat. What does mean something is what I see with my own eyes ie the fact that at times I have aggro for more than 33,4 secs and at times it's less than 33,4 secs. Your far better off working on the basis of observation than worrying about numbers imo its less boring and one should be keeping an eye on things anyway. In some circumstances the more range you have the more taunt you'd want, the less duration you have the more recharge you'd want. I don't taunt slot attacks, damage is a multiplier to it, reduces fight duration, needs to actually hit and I wouldn't wanna run out of end too soon...in fact unless I am end sapped on Shannon I don't get to run out and yes generally tanks tend to get end sapped more so than everyone else in the team.
He will honor his words; he will definitely carry out his actions. What he promises he will fulfill. He does not care about his bodily self, putting his life and death aside to come forward for another's troubled besiegement. He does not boast about his ability, or shamelessly extol his own virtues. - Sima Qian.
Points 17,26 and 28 in this would seem to invalidate my hypothesis and the hypothesis that dmg done is somehow involved. Still leaves me wondering about my Taunt duration enhancement. Think I'll repost this as a bug (misleading text at least). Cheers folks
That link is a player written guide from two years ago - i.e. from before Castle admitted the Devs had misunderstood how taunt actually worked and so isn't totally accurate.
Try searching for Castle's description of how it works
Basically it amounts to Threat=Threat Rating*Taunt Duration Remaining*Damage done. (somewhat simplified)
Taunt itself (and Confront iirc) multiplies this by 1000
All tank and brute primary and secondary attacks have a taunt effect but duration varies.
This is also the reason it is possible under certain circumstances for another character (probably a blaster) to pull aggro off of a tank. - good luck doing this if the mob is actively taunted as opposed to being hit by taunt efeects form auras or attack powers.
Also threat is recalculated for every attack - it does not stack
Mind of Gaia lvl 50 Defiant's first Mind/Storm 'troller.
Deadly Doc 50 Dark/Dark Corr
and lots more on Pinnacle,Union and Defiant
Oh gaias if only my search-fu where greater perhaps I would have indeed found that holy grail for all who seek knowledge of the mysterious taunt alas no.
I was never around for Castles 'What we thought we knew about the mysterious taunt has been found to be mere phantoms and illusions' post so did not know the full heresy of what I quoteth.
But finally, and thank you many times, perhaps my quest has not been in vain, for there before me the truth of taunt revealed. Unfortunatley doesn't really seeem to help with my Taunt enhancement problem as mag doesn't seem to be involved but I am glad I now understand it better.
*returns to his search fu traing* + on + off + on + off
[ QUOTE ]
Taunt mag decreases over time
[/ QUOTE ]
This, sort of. As much as I can remember of Castle's explation, Taunt duration remaining is a large multiplicative factor to the basic threat rating of the player to the mob: it's not a binary effect, although I was often said that it was before Castle figured out it was working differently.
See Paragonwiki.
[ QUOTE ]
Taunt works by multiplying the Threat generated by attacks, with the multiplier dependent on the AT in question, the duration of the Taunt, and the character's proximity to the enemy. Recently[1] Castle create a thread revealing this fact, as opposed to the commonly accepted explanation (and description in the game documentation) that Taunt simply overrode all Threat.
The Taunt power (and Confront, Calling of the Wolf, Warrior's Challenge, Challenge, and Provoke) counts as an attack, so that hate may be gained with just the damage-less Taunt. Attacks made after the Taunt is applied have their Threat multiplied by 1,000 * Duration (where Duration is the duration of the Taunt effect).
AT modifiers, damage dealt, and proximity to the enemy affect the amount of Threat generated. While a Tanker or Brute should normally be able to build Threat much faster than any other Archetype (especially with the help of the Taunt in all of their attacks), Castle's post was prompted by Issue 11 testing with a Tanker using Taunt that was unable to pull enemies away from a Willpower Scrapper using Rise to the Challenge. The combination of the Scrapper's enemy proximity, pulsing Taunt, and constant damage far outdid the ranged Taunt by the Tanker. After further testing, Ghost Widow followed the code logic to discover that the game's internal documentation on the subject (supporting the "Taunt overrides Threat" argument) was incorrect.
[/ QUOTE ]
As for slotting, yes, if you slot taunt enhancements your taunt will be both stronger and longer lasting, so yes, do it, but Taunt+damage will hold aggro better than just spamming Taunt.
I really should do something about this signature.
Non of the maths so far seem to indicate Mag has anything to do with anything let alone duration. The post by Castle appears to be missing, or removed from the US forums perhaps an indication that he to maybe in the process of reassesing the data he presented (this of course is pure speculation). Who dearly love to talk to the man and perhaps find out what he did say in full and where his thoughts are at on the matter at the moment.
The Paragonwiki quote is basically what Castle said.
There is nothing suspicious about Castle's post being missing, there have been several forum whipes since then.
There is no such thing as Taunt mag, only duration. Anything in game that refers to the magnatude of taunt is in error, and actually means the duration.
I really should do something about this signature.
Taunt enhancments state they enhance taunt duration but when slotted enhance taunt mag (according to detailed info) which should be true?