Fantage is one of many free and paid virtual worlds that have attracted 66.4 million active users from age seven to 13, according to virtual world research firm KZero.
There’s Webkinz, a world based around the virtual alter egos of the plush toys found in stores.
There’s Poptropica, a fantasy archipelago where kids ages six to 15 roleplay and complete quests.
Collin Wisniewski, a 15-year-old who lives in New York, was a very active Club Penguin user when he was 10.
He and his friends liked it for the games, but he remembers there was quite a bit of flirting going on.
"People would say 'oh, are you a boy or a girl,’ and ‘oh, do you want to come to my igloo,'" he recalled.
"I didn’t really put it together at the time." What did they do in the igloos?
"They would just hang out and play with each other's puffles," Wisniewski said, referring to the small, furry amoebas that Club Penguin users keep as pets.
"There really isn't that much to do."' This kind of kiddie flirtation is pretty harmless, but most sites prohibit any type of dating.
Club Penguin does not consider dating to be age-appropriate for its seven-to-14-year-old audience, and Fantage goes so far as to replace the words "boyfriend" and "girlfriend" with "friend" in chat. The first is that some parents are uncomfortable with the idea of their young children engaging in any type of sexual role playing, no matter how innocent.
The second is that these sites do attract pedophiles.
When her 10-year-old daughter announced that she had gone on a date to the park with a boy and he’d asked her to the prom, Rebecca Levey was astounded.
"Going to the prom is about seven years away," she wrote in a widely-circulated essay about the online dating life of tweens last week.
Fortunately, all of it — the park, the boy, the prom — was merely virtual.