It's natural for tweens to separate into groups and social cliques. But now their groups extend to online worlds, social networks, and kids' websites with social features. Because kids can communicate anonymously, they can say cruel things to and about each other.

A good place to start: Before they go online, make sure you share tips on how to behave responsibly in an online social world. Make sure they understand that there are no secrets on the Internet and that whatever they post can be seen by people they don't expect and last forever.