WeeWorld is a social networking site designed just for kids where avatars called WeeMees can be created. Visitors to the site can chat with other members using their created avatar, and have the ability to download games and other items.
Habbo Hotel is a free avatar-based chat site for kids that is closely monitored to ensure no inappropriate conversations take place. Kids can sign up for free, and also have the ability to login using an existing Facebook account.
Gaia Online offers a fully-featured virtual world with its own creation story, as well as forums and shops. Members can access several fun games of all kinds, as well as buy items with virtual currency in the shops.
Another very popular avatar site that has won awards is Fantage. The site's moderators take Terms of Service violations very seriously, and the sharing of personally identifying information is prohibited.
Webkinz is a site associated with the popular toy brand of the same name. In addition to creating avatars and playing games, kids can also find information on fun craft activities.
Moshi Monsters allows kids to create and care for virtual pets, without the need for personal information being given out. Kids who use the site interact with each other via their Moshi Monster, and can play games or explore the world.