Why is it legal to pay someone for sex on camera?

I am not sure how to answer this question! Is porn different than a call girl both do have sex for money! Check out the comments from people at digg.com you will be amazed. slate.com — Having sex on camera for an adult film generally won't get Jenna Jameson in trouble, but doing it with a john is illegal everywhere except in parts of Nevada. What's the difference between porn and prostitution?