Found this just a couple of minutes ago and i tried searching before posting but couldnt find anything that explains this.
UPDATED: Apparently there's a horde version of this quest aswell, not sure if it's as useful but i should probably add it aswell. (Thank you drano and xxreaper00
ALLIANCE SIDE!
In Shadowmoon Valley, at the Wildhammer Stronghold you can get a quest, from Zorus the Judicator, called A Ghost in the Machine.
Just finish this quest then grab the new one, Harbingers of Shadowmoon.
This is the quest we want. You'll recieve a pair of goggles which enables you to see the dead who used to live there, and your supposed to kill 12 of them.
HORDE SIDE!
Essentially the same quest. First go to Shadowmoon Village and find Chief Apothecary Hildagard.
Accept the quest A Haunted History. Complete that quest and go back to Chief Apothecary Hildagard, turn the quest in and accept Spectrecles. From here on out its the same.
Now what i noticed is that these undead are level 68-69 and have at the most 5500 hp. I, myself, as a level 69 shaman in greens easily kill these in about 6-8 seconds flat. Even when my windfury doesnt want to proc.
The fine thing about these mobs are:
1) They are neutral, you can choose to pull as many as you want (aoe grinding?)
2) They often drop 1-3 netherweave per kill.
3) They all drop between 3,5s (my lowest) up to 20s+ per kill.
Easy experience and in my opinion worthwhile grinding. Besides, if you dont turn the quest in you can grind them as much as you want (without ever leaving the camp)!!
Hope this helps someone, Just trying to contribute and not just lurk in the mmowned shadows all day long.