An acronym used by Australian writer Jack Heath and now taken up by numerous bloggers, meaning "Most Interesting Thing I Found On The Internet Today".
Person 1: "Dude, you see the mitifotit I posted on my blog the other day?"
Person 2: "Man, no-one reads your blog."
Person 1: "Well, it was totally bitchin. I found this great flash game where-"
Person 2: "Dude, shut up."
To laugh at a joke one doesn't get, with the intention of appearing smarter.
Person 1: "Dude, what's so funny?"
Person 2: "Francis just said 'The one I love has truly moved away.'"
Person 1: "What's so funny about that?"
Person 2: "Uh, I don't know. I was hoping you would."
Person 1: "Oh, so you were lielaughing just now."