Raotrcl was originally thought up by Daniel Remy of California and is a term which is used when a person thinks something is so funny that they want to run around the room while chuckling. Loudly.
It's like a more extreme version of lol except with raotrcl, the person typing it actually thinks something is funny.
Johnny: loling needs to be a verb...
Billy: What would it mean?
Johnny: To chat on a computer aimlessly.