Some web sites that contain personal information make kids easy to locate. If you allow your kids to have a web site, apply this rule: Don't post anything on a web site that you would not be willing to post on the bulletin board of every supermarket in every city in America.
Another great option that addresses all of what your kids might encounter on the Internet: Place a remote monitor (computer screen) in the kitchen or livingroom so that whatever your child is seeing and doing on the Internet could be seen by others at another part of the house. The cost for a monitor and cable is small. Is this like Big Brother? I think it is no different than influencing what books, television shows, or movies your child has access to.