A highly contagious illness, Nataliosis is when someone says that they are leaving the current conversation, when really they are sitting at the computer reading the conversation.
Another case of Nataliosis, also known as Natalieing is when you un-intentionally kill conversations, everytime you speak in them.
The only way to be cured of both cases of Nataliosis is to be run over by a magic unicorn.
1) Courtney killed the convo, she needs to stop Natalieing!
2) She has a severe case of Nataliosis, she was sitting there the whole time.