Often followed by a short conversation, at the end of which the other person reciprocates the usage of the word "Dude" in a manner of agreement or sarcasm.(depending on the case)
B: Alternatively used as a way of getting a persons attention.
*Word Coined By Jacy David Nolen*
Person A: "Dude!"
Person B: "What?!"
Person A: "Daniel Tosh is coming out with his own show on Comedy Central!"
Person B: "Dude! Thats Awesome!"