Auto Shot is a hunter ability learned at level one. It is a basic attack that allows hunters to fire their ranged weapon repeatedly until cancelled. This will automatically activate when a hunter uses any offensive ranged ability (with the exception of Scatter Shot).
The auto-activation when used with any ranged offensive ability can cause you to generate more aggro than you wanted or to break an effect.
Since it is a spell in itself, attempting to use a macro which activates multiple abilities will prevent one or possibly more than one of the abilities from being activated (in other words, you will receive the error message "Another Action is in Progress").
Patch 4.1.0 (26-Apr-2011): Auto Shot now automatically turns off until reactivated once Freezing Trap is cast on an enemy player.
Patch 4.0.6 (8-Feb-2011): Hunters can now use Auto Shot while moving.; Casting Trap Launcher, Distracting Shot, and Scare Beast now cancel Auto Shot when cast. This is to make it easier to crowd control creatures with Auto Shot while moving enabled.
Patch 3.1.0 (14-Apr-2009): 15% ranged haste is now built into the hunter's Auto Shot.
Patch 2.4.3 (2008-07-15): Using an instant ability after Steady Shot will no longer lock out auto shot.
Patch 2.4.0 (25-Mar-2008): Equipping a thrown weapon while in the middle of an Auto Shot will no longer cause animation issues.
Patch 2.3.2 (2008-01-08): /cast will toggle spells again unless the name is prefixed with an exclamation mark, e.g. /castsequence Steady Shot, !Auto Shot
Patch 2.1.0 (22-May-2007): Hunters now have a UI option Auto Attack/Auto Shot that if turned off means that the hunter will not automatically switch between ranged attack and melee attack difficulty when the range changes.
/Patch 2.0.1 (05-Dec-2006): "Auto shot" will be automatically enabled if the Hunter steps out of melee range while in combat with target. "Auto shot" is now reset when casting Aimed Shot. It will no longer activate on resurrection.
Patch 2.0.6 (23-Jan-2007): Auto Shot will be automatically enabled if the Hunter steps out of melee range while in combat with target.
Patch 1.8.0 (10-Oct-2005): Auto Shot is now canceled when you die.
Patch 1.7.0 (13-Sep-2005): Fixed a bug where switching targets would cancel Auto Shot. Switching targets should now continue firing on the newly acquired target.