The uncontrollable urge to check one's facebook every time one comes in contact with a computer.
Sam: "Dude, you've been on the computer for four hours reloading the same page. Don't you have a final exam tomorrow?"
Kyle: "Facebook Fever."
Sam: "No one has posted on your wall in days."
Kyle: "How do you know? They could have posted in between now and the last time that I reloaded the page!"