Your Chill effects reduce the target's speed by an additional 4/7/10%, and the target's healing received. In addition, whenever you deal spell damage, your Water Elemental is healed for 5/10/15% of the amount dealt.
Permafrost is a mage talent that increases the effectiveness of the mage's chill effects, reducing movement speed by an additional amount, up to 10% at max rank 3, and reduces the target's healing received by up to 10% at max rank 3. The additional reduction to movement speed is an additive amount, meaning that a snare that normally slows by 50% will now slow by 60%. This talent is popular with frost mages that do a lot of kiting, either against single mobs or when fighting multiple mobs at once.
The debuff triggered by [Frostfire Bolt] has both the snare and a DoT effect combined, so taking at least two ranks of this talent makes the DoT effect tick one more time.
Patch 4.0.3a (2010-11-23): Now reduces healing by 10%, down from 25%.
Patch 4.0.1 (2010-10-12): Healing reduction at max rank increased from 20% to 25%.
Patch 3.2.0 (2009-08-04): In addition to its existing effects, this talent now also causes the mage's Chill effects to reduce healing received by the victim by 7/13/20%.
Patch 1.11.0 (2006-06-19): Moved to tier 2 and reduced to 3 ranks (was tier 1 with 5 ranks). In addition, now causes Chill effects to reduce the target's speed by an additional (4/7/10)%.
[Permafrost].
[Frostfire Bolt] has both the snare and a DoT effect combined, so taking at least two ranks of this talent makes the DoT effect tick one more time.
Patch 5.0.4 (2012-08-28): Removed. 
