This article might be important for you:
http://www.hollabackhealth.com/2010/12/five-reasons-to-stop-using-emoticons/
Interesting text but I disagree with the most of its contents as it stands for a rather subjective point of view. Like usually, we have a problem that is essentially based on a controversial issue. If it wasn't controversial there would be no argument as none of us here is really stupid. We all have common sense. However, as soon as things are no longer black and white all sorts of disputes are bound to happen. Homosexual marriage or not? Sex with animals or not? Emoticons or not?
Regarding the latter, emoticons are the lesser evil in this highly pragmatic way of communication, where memes dominate the internet space and one must state their sentence with the minimal number of bytes in order to prevent people from answering with TLDR. So what's the greater evil? --- Ambiguity. Without the help of emoticons we are doomed to have our intent misinterpreted. By the way, if you think that emoticons are only used to express sarcasm then you're a step away from malignant paranoia. It's the same as assuming that all people are evil and want to harm you.
That said, I remain at my stance that even though emoticons introduce a certain degree of degeneration from the literati's point of view, they do more good than evil. They give you a hint what the other person is communicating to you. Textual language alone has never been the perfect way of communication. Thus, we must compensate. Ever heard of the adage "a picture is worth a thousand words"? Sure you have. Now isn't an emoticon a picture?