It's alledged that the Emoticon —the seemingly random bit of text that looks like a face on its side eg. :-)— is 25 today (or roundabouts). Professor Scott Fahlman is even owning up to the idea, although I feel that this is one of those things that was just in the air at the time. If not Fahlman, it would have been somebody else.
As you can probably tell, I don't like them. I do get how they are useful in conveying something about tone of voice, but it seems that once you start using them they become line noise, random little observers of your own inability to express something without recourse to winking (or whatever) at your reader. I also think that the have a tendency to obfuscate where you expect them to clarify, in that when I've seen them used it tends to be along the lines of "You wanker :-)". Is the writer happy that the reader is a wanker or are they hoping that smiling while calling someone a wanker somehow makes it all alright.
Then they start to become the whole message:
Possibly expressing that the writer is so overcome by sadness that three keystrokes is about all they can manage.
No doubt there's an article somewhere on the Guardian website by some trendy, wannabe intellectual iconclast about how freeing they are and how they've changed language along with those texting abbreviations (FYI if you say "LOL" out loud to me I will PYITF).
Emoticons are, at best, lazy. There's rarely any real need to use them and if you do please stop and ask yourself why.