Lol

Another way of saying, Your joke wasn't funny, I'm not laughing out loud, but I feel I must encourage you. Or, I don't really care, and since I didn't read what you typed, I have nothing else to say.

Clark: Why did the chicken cross the road?
Luke: *bored* ugh, why?
Clark: Because he wanted to get to the other side! HAHAHAHAHAHAHAHA

Luke: oh.. ha. Ha. Ha. Lol