Never give our personal information such as your name, home address, school name, or telephone number, passwords, birthdate or years, or credit card information.
Never write to someone who has made you feel uncomfortable or scared.
Do not meet with someone or have them visit unless you know them. Don't tell anyone your schedule; don't say where you'll be hanging out. People are often not who they say the are. Someone who says that they are a 12-year old girl could really be an older man. 1 in 5 kids will be sexually solicited online.
Tell your parents right away if you read anything on the internet that makes you feel uncomfortable.
Don't fill out any "fun" questionnaires that are forwarded to you, even if they are from your friends. Remember, you are in a world where everything can get forwarded. All those personal things about you could land in the hands of someone who could use them to harm you.
Make sure you know everyone on your friend or buddy list. If you haven't met the people face-to-face, they may not be who they pretend to be. Instant messaging strangers is an invasion of their privacy.
Don't answer emails or IMs from people you don't know. If you don't know who the person is don't respond even if they say a name of some you know. It could be a lucky guess.
There's no such thing as "private" on the internet. Anything you post on the internet is out there FOREVER. Even if you think you have deleted it, it is still out there for people to find.
Be careful about posting pictures of yourself. Pictures with identifiers like where you go to school can be shopping lists for online predators and other creeps.
Don't send pictures of other people. Forwarding or posting an embarrassing picture of someone else is a form of bullying.
Don't download content without your parents' permission. Many sites have spyware that will damage your computer. Other sites have really inappropriate content. Your parents can check your computer's URL history, so you can't hide where you have been.
Never share your password with anyone but your parents.