2002 Nissan Xterra broken piece (what is it?)

Hey guys. I know very little about cars. I noticed a snapped bar under the vehicle close to the back. Hopefully someone can tell me what it is.
http://i58.tinypic.com/2dwhtmv.jpg

looks like a sway bar. i would replace it

looks like a sway bar. i would replace it
Thanks for the reply,

Is it dangerous if its not replaced right away?

if you don't want to replace it i would remove it, if it drops down to far might start creating sparks