Celebrities galore on Stardoll

There isn't much to Stardoll, one of the more popular kiddie virtual worlds. At its core, the model has much in common with traditional paper dolls.

Girls with an average age of 13.8 can log on, pick celebrity dolls and dress them in high-end clothing lines from brands like DKNY and LVMH. There's a chat function too, but little else.

Despite (or perhaps because of) its simplicity, the site has grown to some 7.8 million unique visitors a month. It has over 14 million registered users and is now published in 15 languages, according to The New York Times Magazine.

The site also makes money — a rare characteristic amongst web 2.0 offerings. For $6 a month, users can upgrade to "Superstar" status.

Superstars have access to exclusive items in the "starplaza" mall, like Heidi Klum-branded necklaces.