The act of hijacking a facebook thread for your own purposes and driving it wildly off topic. Sometimes kading can be an intelligent conversation that simply has nothing to do with the original topic, but most of the time kading is a form of spamming that annoys everybody not participating in the kadage. The easiest and most common way to kade a thread is to take turns posting lines from Dr. Horrible's Sing Along Blog, Charlie the Unicorn, or the Potter Puppet Pals.
This thread has been kaded!
Stop kading, you guys; I'm getting a million notifications!
Random fb status: Charise is tired from a long day
friend: Aww! I hope you get some rest soon!
kader1: I love pickles!
friend: What does that have to do with anything?
kader1: Snape, Snape, Severus Snape
kader1: Ron, Ron, Ron WEASLEY
Charise: guys, come on, why do you always have to kade my status?