Considering text doesn't have nearly as much explanatory power as the spoken word, especially in person, with facial expressions and subtle differences in tone being equally important, if not more so, than the words themselves...Z of the Na said:snip
I'm going to have to disagree. I find that using emoticons in texts and over Facebook a great way to establish whether or not you're being playful, serious, tongue-in-cheek, sarcastic, etc. There's no other way to even come close to imitating the subtleties of human interaction.
Edit: That isn't to say that they can't be extremely annoying if used too often or in the wrong way, only that they have a plethora of uses, that vary depending on who you're talking to.