Rule 16 states that there are no females on the internet - specifically in role-playing games and chat rooms.
Expanded Rule 16 states that:
a) All internet men are men
b) All internet women are really men
b) All internet children are policemen
Player 1: Did you check out Rocket Dog' profile? She is so hot, so I PM'd her and she is sexy cool!
Player 2: Dude, remember Rule 16. She's really a 40 yo dude in his living in his mom's basement!
Player 1: No! She's real and she likes me!