Why would you use ROFL when you could just use lol or haha and most or all people would get it. ROFL did my head in I spent ages just thinking about it. IMO took me ages aswell and then people had to go and add a H in there (IMHO) In my honest opinion.
ROFL (Had no f***ing clue, what that meant lol)
STFU (Thought it was "Stuff You")
FTW (Thought it was "F**k the world")
ZOMG (Didn't realise, it was an exaggerated version of "OMG", but still don't get why the "Z" is there??)