I found this information at Patrick's Place. It makes me very glad my children are grown up.
"How about CD9? Ever seen that one? If you have, it’s your child’s way of alerting whomever they’re talking to that you’re around. CD9 means “Code 9,” which means that parents are near the computer, and might see what’s being discussed. And if they’re using that kind of code, there’s a good chance that there’s a reason they don’t want you to see what else they’re talking about. The same goes if you see PAW or PRW. These codes both mean “parents are watching.” POS means “parent over shoulder.'"
25 slang terms all parents should know.