Citing the 3 million registered users that Barbie Girls, Mattel’s new virtual world for girls, has chalked-up in the last 2 months alone, Duncan Riley of industry blog Techcruch says that one thing is very clear: virtual worlds are going mainstream and the user base is dramatically shifting from being predominantly male to majority female.

Barbie Girls allows users to customize Barbie dolls, dress them up, create virtual homes, adopt pets and chat with other users. The service is free to play with a revenue model focused on the purchase of virtual goods.