ROTFLMFAOAKTC 

Rolling On The Floor, Laughing my Fucking Ass off and Kicking the Cat.
An acronym used as a more extreme form of the commonly used 'Rofl,' which is, in turn, a more extreme variant of the IQ lowering 'lol.'
It's more a random expression of "Hol Sh*t!!" than anything.

Lame: lol i pwnz0rd u at teh h4xxx
Not so lame: I can at least spell, noob.
Lamest: ROTFLMFAOAKTC!11! U GOT T3H PWNZ0000O0O0O0RRRZZZTT!!1 LOLOLOLOLOLOL111
Normal person: Are you on PCP?

ROTFLMFAOAKTC by Kristoffe June 18, 2007

ROTFLMAOASTC 

It's the acronym for: Rolling On The Floor Laughing My Ass Off And Scaring The Cat. It expresses extreme amusement for a funny situation; it is also used by nerd people in order to conquer the weak-minded noobs of the web.

Noob: "Heya m8!"
Nerd: "Wtf?!"
Noob: "C'mon, wazzup?"
Nerd: "Stop bothering me and lemme play WoW in peace"
Noob: "Wottaffukka is that?"
Nerd: "Stfu, noob! Rtfm! I'm gunna enslave you, rotflmaoastc!"
Noob: "Yes, master?"
Nerd: "u.u"

ROTFLMAOASTC by SwatMaster88 March 4, 2009

ROTFLMFAOAICGU

An acronym commonly used by seniors in response to a funny comment; Rolling On The Floor Laughing My Fucking Ass Off And I Can't Get Up

comment: I've run out of Depends.
reply: ROTFLMFAOAICGU

ROTFLMFAOAICGU by rjratman November 3, 2012

ROTFLMFAOASTD

Rolling on the floor, laughing my fucking ass off, and scared the dog

Usually found in Instant Messages, typed when someone has said something REALLY funny, like, "Why won't my new home-built PC start up? Should I have used those little brass stand-offs between the case and the motherboard?" The proper reply to such stupidity would be ROTFLMFAOASTD!

ROTFLMFAOASTD by Da Dirty Q-Tip October 18, 2002

ROTFLMFAOWOTCC 

Rolling on the floor laughing my fucking ass off while on the computer chair.

ROTFLMFAOWOTCC!, That was funny!

ROTFLMFAOWOTCC by Chino November 14, 2003

ROTFLMFAOASTD

Commonly spewed by AOL'ers after another AOL'er says something even too stupid for the average AOL'er.

AOL'er 1: I LOVE ZSNES!!!!111111111
AOL'er 2: ROTFLMFAOASTD!!!!!!!!111111111111111111

ROTFLMFAOASTD by Parasyte January 28, 2003

rotflmfaostc 

rolling on the floor laughing my effing ass off scaring the cat... a huuugee over reaction to something vaguely funny..

Person 1: OMG DEWD I JUS OWNEDIZZLED LIKE 4 GUYS IN A ROW!!11!one!
Person 2: ROTFLMFAOSTC!!!!!! LAWL!! oh my eff dewd, i was lawling all over teh floor wen u tol me that!!1!11!11!

rotflmfaostc by t3h pwnerer July 29, 2008