Both multishot and strafe are skills for the bowazon of Diablo 2. They are both considered the best skills, but most people prefer multishot. Both can hit several enemies with one shot.
Strafe enchants your arrow to make it guided - after hitting an emeny, it continues to hit another one, and another one, and another one...

Multishot shoots a single burst of several arrows, making you shoot more arrows/second. Unfortunately, a larger percentage of arrows miss when using multishot.

The debate is, which one is better?
Before patch 1.04, most players would've said strafe. In 1.04, however, strafe has a considerably smaller range, and a bug making strafe do higher damage has been removed. There are still many amazons that prefer strafe, but they're losing numbers....

Strafe pros
Aims automatically.
Mana cost remains fixed when you put more points in the skill.
Damage/arrow increases when you put more points in the skill.
Fires at monsters in all directions, sometimes even if they're behind you.
If monsters are lined up in a row, it can sometimes hit a single monster twice.

Multishot pros
Can hit monsters even if they're off screen.
Fires more arrows per second.
Is available at level 6, strafe at 24.
Better for hit-'n-run attacks, since it takes a lot less time to fire.

Strafe cons
Major con ---> When you've fired a strafe, you are LOCKED IN POSITION until THE ARROW IS FINISHED STRAFING. This is sometimes lethal, if you have many points in strafe it'll take quite some time (perhaps 0,5-1,0 seconds).
It has really poor range compared to multishot, sometimes it won't even hit enemies that are on screen if they're in a corner.

Multishot cons
Mana cost increases when you place more points in it.
Can only hit every single monster once.
Doesn't increase damage.