From wow.incgamers.com

Statistics

Talent Improvements

The talents below affect Curse of Weakness in the following ways.

Affliction Tree

Talent: Contagion
Effect: Increases the damage of Curse of Agony, Corruption and Seed of Corruption and reduces the chance Affliction spells will be dispelled.
Statistics: 1 point = +1% damage & -6% chance skill is dispelled, 2 points = +2% & -12%, 3 points = +3% & -18%, 4 points = +4% & -24%, 5 points = +5% & -30%

Talent: Grim Reach
Effect: Increases range of Affliction spells.
Statistics: Rank 1 = 10% increase, Rank 2 = 20%.

Talent: Improved Curse of Weakness
Effect: Increases effect of Curse of Weakness.
Statistics: 1 point = 10%, 2 points = 20%.

Talent: Improved Drain Soul
Effect: Returns mana if target is killed by you while you drain its soul. Also, Affliction spells generate less threat.
Statistics: 1 point = returns 7% mana & 5% less threat. 2 points = returns 15% mana with 10% less threat.

Talent: Suppression
Effect: Reduces chance enemies resist Affliction spells.
Statistics: Rank 1 = -2% chance, Rank 2 = -4%, Rank 3 = -6%, Rank 4 = -8%, Rank 5 = - 10%

Threat Level

What is the threat level of Curse of Weakness.

Uses in PvP

Please feel free to add a bullet list of uses within PvP or editorial if you have more to say. What use is it against other builds, what skills can it be used to counteract or prevent. What skills does it work well in combination with.

Uses in PvE

Please feel free to add a bullet list of uses within PvE or editorial if you have more to say. Which creatures/bosses in particular is it useful against.