ELEMENTARY AND MIDDLE SCHOOL
Whyville.com: Free, designed for kids 8-15. Like Webkinz and ClubPenguin, it involves playing games to earn virtual money (in this case, "clams") for use in building an avatar. Rather than being represented as a cartoon animal, Whyville members create avatars that represent their physical selves. That's one step closer to the vibe of more grown-up sites, but it's still more a virtual world/gaming space than a true social networking site. Chat among new members is restricted to prewritten phrases, but those who pass a "chat license test" (to show they understand online safety) have more freedom to type personal messages to friends. Some words are blacklisted. This site doesn't hawk toys and is more educational than most.
Dgamer.com (Disney XD): Access is free with purchase of certain Disney video games. Kids have avatars, can chat and send virtual gifts, but the priority is gaming via the networking capability of a Nintendo DS. The basic chat function allows only prewritten phrases. Parental approval is required for more advanced chatting ("Open Chat" and "Speed Chat Plus"), which is watched over by human moderators. A warning: Teach kids the difference between Dgamer's "public chat" (where strangers can read and join their conversations) and "private chat" (limited to those you've approved as friends).