When you critically heal with a single-target direct heal, you summon an ancestral spirit to aid you, instantly healing the most injured party or raid target within 40 yards for 30% of the amount healed.
The second target will be healed for up to 30% of the total healing done to the first target, including the 200% critical effect multiplier. Ancestral Awakening currently benefits from Purification in a rather peculiar way: the 25% bonus is applied to the healing done by the spirit. Since the 25% bonus was already included in the heal that triggered Ancestral Awakening, this means that the talent effectively gains the bonus from Purification twice, healing for 12.5/25/37.5% of the original heal. In practice, this means that your critical heals will heal for 275% of a non-critical heal, distributed across two targets.
Hotfix (2013-07-19):Ancestral Awakening should now properly interact with [Battle Fatigue]. Previously, Battle Fatigue was being incorrectly applied a second time while healing nearby party or raid members.
Patch 4.0.1(2010-10-12): Moved from tier 9 to tier 5. Now only mentions single-target direct heal spells.
Patch 3.1.0(2009-04-14): This talent now accounts for your ineffective healing, rather than effective.