How is this not prostitution?

The afternoon radio show I listen to was discussing online dating sites this evening. One of the sites they mentioned was WhatsYourPrice.com - a site where men bid on dates with women. The tagline is "Everyone has a price." Men log in as "the generous" and women log in as "the attractive."
 

For the Generous
DATE BEAUTIFUL PEOPLE® GUARANTEED

You have high standards and you won't settle for less. You're willing to pay to date beautiful, gorgeous or sexy people. For the right price, WhatsYourPrice.com is the only dating website that guarantees you will date more attractive people than you can handle.

Sounds like chick shopping to me.

For the Attractive
GET PAID FOR DATING® GUARANTEED

No matter what you're seeking, finding that perfect relationship takes time. However, dating doesn't have to be a waste of time. If you're beautiful, we are the only dating site that guarantees you will get paid while you spend time meeting fun and generous people.

Ummm... yeah.

On the home page, there are profile pictures on each side - the generous and the attractive. Care to guess how many on the "attractive" side are naked? Several.

So how is this NOT prostitution? I guess they cover themselves (so to speak) the same way escort businesses do - the women are paid for "companionship" and not necessarily for sex.

But it sure is implied.