I got curious and downloaded it on my iPhone 4S
Here you get to shop till you drop (the coffee sign on the upper right side indicates your energy level), of course you can use the diamond or the bucks to purchase clothes, shoes and accessories. I have an initial of 14 diamonds and if I want more, I'll have to pay with real cash (Paypal or Credit Card I guess). But the bucks are added to your account, I'm just not sure how the rate per hour.
Then you get to compete with other Fashionistas. As you can see I just lost.
You battle against your hotness level (I'm hotter), Clique Size (I got no friends) and Closet Bonus (I need to shop more!).
I am no Fahionista but I love dressing up my dolls, so I might play a little more.