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!
a over exagerated version of lol which means rolling on the floor laughing my fucking ass off till i die, usually used by ppl who think their too good to just use lol, or just plain laugh.
person1: OMG he just fell of that building person2: rotflmfaotid
person1: why didnt u just laugh?
person2: cuz im too good to