@umbra21 - I think emoticons have already become part of written language in some cases, because written language is now being used in ways it never has been before. People are able to communicate in real time using written language and in order to keep their communications as nuanced as they might be face-to-face they need extra symbols to add context and tone to the words.
You don't just use a smiley face in order to express that you're smiling. Depending on what the rest of the words say, it has different meanings, just like any other kind of punctuation does.
I think it's kind of ironic that we're entering a modern world and using pictographs to communicate, considering they are usually seen as primitive, but they work and they can actually be quite subtle.