Thanks to a merger with teen site Piczo and a launch of the younger-skewing Paperdollheaven.com, the girl-targeted online entertainment hub at Stardoll.com has formed the Stardoll Network.

The three sites combined are set to reach more than 20 million users on a monthly basis, with the majority of traffic being generated by girls between the ages of five and 20 years old.

Stardoll.com already boasts more than 27 million members worldwide who flock to the site to dress up MeDoll, design and sell virtual clothing, get the latest on their favorite celebs, and more. A full 51% of the site’s traffic comes from Europe, with 40% in the Americas and 9% from Asia-Pacific.

The San Francisco, California-based Piczo, which has more than 30 million registered users, encourages teens around the world to creatively express themselves by building their own web pages. Piczo has grown to become the number-one destination for teens who want to build and customize their own Web pages. It’ll run independently of the Stardoll Network.

Meanwhile, Paperdoll Heaven, which launched this past December, offers free activities to members, from dressing up virtual dolls and pets, decorating and playing in a dollhouse and play online games.