Rotflmao

[PussyCat]

roll on the floor laughing my ass off

[Little_Girl]

Rolling On The Floor, Laughing My Ass Off

[Couch Potatoe]

A chatroom abbreviation used mainly by imbeciles, usually in response to something mildly, often very mildly, amusing. People who use this type of shorthand should be avoided like the Spanish flu.

[Mark Zuckerberg]

The resulted offspring in the combonation of the two most powerful words in the history of the intarweb.

[Jessica]

Abbreviated form of Rotten Flamingo (if spelled oddly)
Chat/MSG speak for Rolling on the floor laughing my ass off. For the insanely lazy and long-winded.

[Jessica]

it means Rolling On The Floor Laughing My Ass Off.
its usualy said when someone says something extremely funny. it comes from Rotfl (Rolling on the floor laughing) and lmao (laughing my ass off. it is often used in the same case as lol (laugh out loud).