WoW - Curious about Hex of Weakness

I was looking at this spell and was wondering, does this stack?

The actual description says "Weakens the target enemy, reducing damage caused by 35 and reducing the effectiveness of any healing by 20%. Lasts 2 min."

Next question is, does that mean the effectiveness of any healing cast OR recieved by the target, or both?

With 4 priests casting this on the same target (say dps warrior in arena's), any healing cast on him reduced by 80%.

Easier to cast on the healer, then any healing cast BY him would be reduced by 80%.

Cast on both the healer, and the target of the healer could mean 20% of healing actually reaches the healers target. If the same curse is on the target too, that would mean just 4% healing reaches the target.

Of course all that time would be better spent casting dmg spells. BUT, if you can't burst dmg them down anyway, then maybe not.

Can someone enlighten me on what is possible with this?

As far as I know the healing is the same as the damage, ie, it lowers the ammount of healing put out by the affected target by that ammount.

And no it won't stack, same as Curse of Weakness, Curse of Shadows/elements etc don't stack; would be just too powerfull otherwise :)

It actually reduces the incoming healing, like wound poison or mortal strike.

Shogun is correct with the non-stacking.