If you are older than 10 years old and not a catcher, wearing a baseball cap backwards makes you look old, stupid, and foolish. If it's a designer cap, it makes you look not only foolish, but fiduciary irresponsible.
The only legitimate reason to wear a baseball cap backwards in style might be to emulate a black gangsta because one covets their lifestyle, popularity, and association with being street-tough. Of course those who wore them in an eccentric fashion, tended to wear them to the right or to the left, to either communicate directions to others or to indicate gang affiliation.
On the other hand, from the Urban Dictionary: "Wearing your baseball hat backwards means your ready to perform oral sex immediately (don't have to waste time to turn the bill out of the way). "
I'm just waiting for 0bama to begin hanging a red or blue bandana out his hip pocket. Let the gang wars begin.