Another variation of the "rofl" (Roll On Floor Laughing) phrases. This one is derived from Chairman Mao, the deceased leader of the CCP. Used to describe something/someone/an action/event that is hilarious, and possibly Communist in nature. The term itself also contains the acronym for "roll on floor laughing my ass off," a phrase heard in online games and in instant messaging conversations.
You're thinking about joining a commune? That's Chairman RoflMao!