Emoticons aren't generally what one thinks of when talking about art. In my experience, though, I find that they're just as valid as any form or medium. In recent years, emoticons have almost become a language of their own due to the popularity of Emoji.
I tend to prefer my emoticons hand-pixelled, however, which is why I made Pixel Emotes. Because, as ubiquitous as Emoji are in today's society, they lack the character and style that comes from a hand-made emoticon. There's something to be said about being able to reproduce a feeling on a 15x15 circular canvas, too.