I'll explain it in ascending temporal order:
1) In 1939 a grayscale movie was produced called "The Wizard of Oz". It starred a fictional character named Dorothy, who lived in Kansas on a farm. Long story short, she and her dog were wisked away to a strange but magical land by a tornado, she goes to see the "wonderful Wizard of Oz" along with people she meets along the way to see if he can send her home, defeats wicked witches, and wakes up in the end since it was a dream. The movie has since become a classic, with various parts entering pop culture. One of these is a quote about not being in Kansas anymore, which has been used in everything from casual conversation to the 1999 film "The Matrix". Other elements include the dog named Toto, the witches, etc.
2) Throughout all of my life at least, it has been a common occurance that any Kansan outside of the region surrounding Kansas has a good chance of having pop culture elements of "The Wizard of Oz" used as a joke including them.
3) A spoof of the classic motivational posters was shown here, including an image of a strange, digital environment with the title "KANSAS" and the infamous quote below it. This builds on "The Wizard of Oz" movie.
4) I posted a few common things people say to Kansans when their place of origin is discovered.
5) Celtic posted one of those, including myself in the joke. I am from Kansas...hence the connection.
Does that make sense?