I just discovered these adorable little plush animals called Webkinz that seem to be attracting kids to the Internet in the droves. Each animal comes with their very own secret code that if typed into the
Webkinz site will take kids to an online virtual version of their new pet.

Once online kids choose names for their virtual pets and dress them up and accesorize them, much like adults do with their Avatars. They're also given virtual homes where they must care for their pets and make sure they are fed and happy.
They are given a certain amount of virtual money to purchase food, clothes, furniture etc... But then they must compete in trivia games and other activities geared toward learning to earn more money to care for their pets.
They can also invite other virtual pets over to chat, although chatting consists of choosing phrases from a set list so everything remains kid friendly.
It has all the elements of a social community and virtual reality rolled into a PG package, plus an adorable plush animal for the real life.