I found this. Man am I getting brain dead with old age . . .
I misread the Thotbott entry (or quickly glanced and saw the one above or below it) and was looking for this as a survival skill when it is actually a Marksman skill.
It was sitting there and apparently I had not noticed that I had gotten a new level 1 skill when I picked this up at 62 so had not added it to my key setup (which is FAR too cluttered with my hunters). Will have to check it out now. It looks like it just does a bunch of extra damage and even more if the target is 'dazed'. I will have to test that last part out and see just what they mean by dazed. Like if stunned = dazed or not.
As to aimed shot. Originally I got that on all my Hunters since every hunter alive sings the merits of aimed shot. Then was VERY disappointed with it. It takes sooo long that I can get 3 normal shots off in the same time and do far more damage and get two extra chances to mess up spell casters. So when they redid the Hunters and gave us all a free respec I did not take aimed shot with any of them and do not miss it at all.
It seems that many use this as their 'pulling' shot when I am pulling and not just supporting my pet as he dashes into combat, I prefer the DoT sting shot or the high damage sting (forget the name but it is a one time shot and not a DoT so necessary for when I plan to freeze trap my target and take omn his friend first).