Phrase used as an add-on to sentences. "In America" fulfills the function of a prepositional phrase, though it is often used as a sentence fragment, and is used to convey an almost sarcastic outlook regarding the American mindset of independence and superiority, or a sincere outlook of such views, which is even scarier. This usage was started by LittleKuriboh's Yu-Gi-Oh the Abridged Series, which was first posted on youtube, but is now available other places as well.
This is the greatest movie ever. In America.