I always thought an emoticon of pacman would be cool on web forums, the part where he kicks the bucket and his mouth opens all the way and then he disappears.

I reckon that would be a good way to express contempt without the risk of saying anything offensive and starting an argument.

If anyone were to take it the wrong way and get offended it would give the person who posted the emoticon time to cool off and then give a more measured retort that doesn't cause offence.