"Although Second Life has received the most attention from marketers and the press, its traffic is low compared with the crowds at virtual worlds specifically geared for children and teenagers," notes the report, titled “Kids and Teens Online: Virtual Worlds Open New Universe.”

eMarketer pegs the appeal for young folk down to the marriage of video game elements with social networking and communication -- connecting and communicating are "the two recurring themes" for online youth, it says. It adds that virtual worlds also allow kids to tap into their creativity, indulge their desire for self-expression and exercise their proclivity for exploration, compounding their appeal.

“The bad news [for marketers],” says Debra Aho Williamson, senior analyst and author of the report, “is that it is difficult to know what all this virtual interaction really means. What value is there in a person’s avatar drinking a Pepsi? Or wearing a shirt bought from a virtual store? What if a person’s virtual activities have no bearing on their real-world activities?”