That is why parents need to get savvy with computers and the Internet. They need to set up an ethernet in the house, put NT (Small Business Edition) on the network. Then, they can restrict when the child is able to be on the computer altogether. They can set up setting that automatically "kicks off" the child (identified by their userid/signon) at a certain time. So, they aren't up at all hours, talking to God only knows who. In addition, they can set up very restrictive web preferences (similar to Web Nanny, but more powerful) depending on their child's age.
Unfortunately, most kids know more about this than their parents do.