lol, k

(1) Originally used as in a "srsly" fashion to express laughter and agreement (2) Should be now used as a way to show sarcastic submission (i.e. you want to tell the noob not-so-subtly that he's really making an ass out himself)

(1)
"Ur avatars so funnay n kewl!!1 OMG!!!1"
"LOL, K"

(2)
"Can I borrow $10? I'll pay you back?"
"LOL, K"

"Am I FUN or what?"
"LOL, K"