Used to indicate that one does not want to see, hear, know, or have anything to do with something. Used for comic effect.
Originates from an alleged, bad English-to-Chinese-to-English translation of Star Wars Episode III. In the end, Darth Vader's infamous "NOOOOOOOOOOOOOOOOOOO!" is subtitled "DO NOT WANT!"
"Check it out guys, naked photos of Donald Rumsfeld!"
"DO NOT WANT!"