Virtual worlds was something I never thought I'd be interested in, let alone allow my 6yr old to play. Alas, as with most of my other ideas concerning technology and parenting, this one has also been drastically changed.
You see, I'm a dinosaur in technology terms. They were still teaching girls to take shorthand when I was in high school. I was thirty before I owned a computer and I still have yet to ever send a text message (doubt I ever will).
However, I love the Internet! The access to knowledge is so fantastic to me, it's like having The Smithsonian Institute right next door and open 24hrs a day. Without it, I know my son would not be getting the education he is. Yet, I still never understood the gaming attraction and combining gaming with the social networks of virtual worlds, just seemed bizarre to me.
My son, on the other hand is infatuated with the idea. He currently visits three online worlds, Roblox, Webosaurs and now Wizard 101. I have to admit Webosaurs (which is a dinosaur world) and Wizard 101 (which is a "Harry Potter like" wizard world) look like fun. I think they would be great for most children who like imaginary play.
I did have to limit which areas of Roblox he plays with because some of the games are too violent for my liking. Even though the characters look like Lego people, the Lego Co. has nothing to do with this website and many of the games are created by players that are supposedly children 8-18 years old. I just know that they spend too much time blowing up people and things for it to be appropriate for my son.
Both Webosaurs and Wizard 101 have led to great discussions and new vocabulary words. Since he has become interested in medieval times, I am going to start him reading the Harry Potter series. Webosaurs has educational videos placed in the game which have expanded his knowledge of dinosaurs and the prehistoric timeline.
I only let him play in safe chat mode (he only has a predetermined list of phrases he can use to chat with) and he only plays the free versions for now.
So I guess you can teach an old dinosaur a few new tricks and maybe teach your children something new at the same time. I'm sure there are other virtual worlds for children as well, but at least these two can be educational and fun.