The word "exploitation" by it's exact translation is divisive and open to interpretation. My thoughts are that exploitation is where a person is forced to do something against there will, because they have little or no other choice. But it could be argued that I only translate it to this context because it allows me to sleep soundly at night, believing I have done no wrong. Others may argue that the very fact I indulge in sex for cash in a third world country means I am exploiting a less well off society for my own needs. This is probably a valid argument.
However, as seven mentioned earlier, we could all argue we are being exploited in our own society by the rich business owner, if you wanted to perceive things in that manner. For example, I work my ass off usually 60 hours a week, and although I receive a generous remuneration, only my boss is getting rich through my hard work. But i don't feel I am being exploited, because I am not doing it against my will, I am doing it to make ends meet.