Many professionals recommend entering into "code-of-conduct" contracts for Internet use with your children.  Family contracts for Internet use are similar to family contracts for cell phones, car privileges, or household responsibilities.  By establishing guidelines for appropriate use early on, children will know their limits and act accordingly.  You can also delineate the consequences for any inappropriate behavior.  Once you have established your expectations for your children's use of the Internet, you can create a contract for children and parents to sign.  You can use one created by others (see below), or you can create your own.