This refers to what is known as the “Pink Cube” phenomena. When you log into the Mists of Pandaria beta right now, basically no matter where you go there are a ton of these giant pink cubes covering art assets everywhere. What’s funny is it was something in one of the latest updates that broke it, when merely a week ago it was fine.
So us being the wonderful and horrible nerds we are latched on to these amazing pink cubes and started yelling out Reboot! I have personally dubbed the expansion Reboot Azeroth: Incoming Game! Now I just wander around the beta looking for Bob , Guardian #452