My pal and coworker John pointed out that the internet meme "rofl" is being tossed around a little too lightly these days. People very rarely ACTUALLY engage in the act of rolling on the floor while laughing, and he wanted to see the usage tightened up a bit.
To that effect, I have submitted the new abbreviation "crofl" to Urban Dictionary for review. "crofl" is short for "Courtesy rofl", to be used in the instance that one is not really interested in rolling on the floor laughing, but wants to let someone know they appreciate their attempt at humor.
For example, say you receive the following joke via e-mail:
Hey guys, you'll think this joke is great!
What kind of monkey can fly? A hot air baboon!!! HAHAHAHA!!!
If this person is a coworker, you may not wish to strain your relationship by not responding at all, so you could reply with crofl to let them know that even though you are not really laughing out loud, you appreciate the gesture.
EDIT: I am pleased to announce that Urban Dictionary has accepted my submission.