With Improved Precise Shot stance active, your ranged attacks pass through and potentially damage all foes in the projectile's path. Your ranged damage is reduced by 20%.
Passive: Your Ability Score Modifier bonus to damage for Longbows and Shortbows improves by 50% (stacks with Precise Shot).
Notes
A Ranger or Dark Hunter gets this feat for free at level 11, even if he does not meet the prerequisites.
AOE Ranged Attacks explode on the first enemy hit by the attack, and do not penetrate further. However, they still receive the -20% damage penalty.
Many special attacks, even those that usually affect only a single target, can affect all enemies in the path.
The projectile continues beyond your selected target.
Race height matters. Tall races, such as Bladeforged, shoot their projectiles from a higher elevation. When targeting smaller enemies, projectile travels downwards and often harmlessly flies above the head of nearby enemies. Targeting is easier for smaller races, particularly Halflings and Gnomes.