Remember that people online may not be who they seem. Because you can't see or hear the person, it would be easy for someone to misrepresent him or herself. Remember that not everything you read online is true. Be very careful about any offers that involve your coming to a meeting or allowing someone to visit your house. Report suspicious activity.
Some conduct is illegal in both the real and the virtual world.
If someone is harassing your child, keep copies and records of the messages and let the authorities know. You may also wish to notify the systems administrator of both your service and the service from which the message was transmitted. Make the Internet a family activity. Consider keeping the computer in a family room rather than in the child's bedroom. Discuss these rules and post them near the computer as a reminder.