A prostitute is someone who works in public places like brothels, an escort who works secretly using internet...
Practically I do not see any difference...
Sometime I would like to shout these words in a supermarket just to see people's reactions:
"People, I am here and I am an escort, a prostitute, a slut, a bitch or whichever of the words you choose.... the truth is that I exchange sex for money and I am very proud of my job"