This is a double exploit for the Chakram - shuriken cloud demon hunter ability:
1st expolit is just like the monk sweaping wind trick - You can equip a heavy hitting weapon ( even a melee weapon! ) and then use chakram and replace your weapon to whatever you usualy use and the damage/abilities of the shuriken cloud will be of the weapon you used to cast it.
2nd exploit is if you use shadow power right before you use shuriken cloud it will have the life steal ability for the entire duration of chakram!
Combining these abilities you can create a demon hunter that can deal and heal a lot of damage of mobs it touches ( very useful for bots... )
Edit: To clarify that the 2nd exploit does not require you to switch weapons.