Smileys:
The purpose of the smileys is to stress a point or indicate your mood when relevant. Reading a few lines of text does not show much of the writer's intonation like in real life conversation where body language and facial expressions are important to get the message across properly. An apparently offensive message can be smoothened by the addition of a smiley that tells the readers that you're not all that serious. Conversely, a sarcastic post can be highlighted by adding the right smiley.
The over-use of smileys, or their addition out of context, can be annoying. What's the point in adding a smiley firing guns, for instance, when all you have to say is, "yes, you're right"? The parsimonious and appropriate use of smileys is therefore recommended.
