Acronym standing for "Random Acronyms For The Win." Used after a string of other acronyms, especially if the user seems to be throwing them in randomly.
OMG I am ROTFLMAO at your lulzy jokes. You've got to STFU b4 I bust a nut. Also, RAFTW.
Variant on the word "awesome" and a play on the more popular "ZOMG". Generally used sarcastically to illustrate that something is not actually awesome, in the same way that 1337speak is not actually cool.