shrug technique and what is this exercise for.....

[slim]

1) When u do shrugs, is it better to go straight up and down or make a circlar motion with ur shoulders?
2) There is an exercise where you lie down on a bench and hold a dumbell with 2 hands so that the dumbell is prependicular to the ground and your elbows are almost locked so that the dumbell is over your face. Then you slowly lower the dumbell in a circular motion so that the ending position is with your arms stretched over your head and then u bring it back to the original position above your face. What muscle groups is this for and is it a good exercise?

thanks