Most people know this song from Van Morrison and Them's cover, but not many people know what it's actually about. The "county farm" is a reference to Parchman Farm, the Mississippi State Pen. The man whose been prisoned there is begging his girl friend not to go down to New Orleans because the only reason she'd be going to New Orleans would be to work as a prostitute.
Living in Asia, there's definitely a different view of prostitution than at home. Korea keeps up an innocent veneer, but, like most of us, beneath it there's a lot of dirt. Once you learn to read the signs, literally or figuratively, you start realizing that prostitution is everywhere.
A few years ago, the government made it illegal, but I think it was pretty much for the same reason they made dog-soup illegal, for international image. As far as the dog restaurants go, the only difference is that the meat isn't regulated. On the prostitution side, they cracked down on the red-light districts, but the more expensive "Room Salons", business clubs, and massage parlors weren't really affected, leaving the poorer men complaining that only the rich can afford prostitutes.
Things you should be weary of in Korea are usually any bars with the words "business" or "room" attached, massage parlors with conspicuous names (there's a Yahoo! Massaji" across from my house, and they aren't an internet company!), "hair salons" with double barber poles, and "coffee" houses with hearts on the billboard.
Usually, the girls ran away from home and quickly become under the control of the pimps, but there are also the ones who do it to pay for their university books or buy an expensive Louis Vouitton bag or something like that...