Japanese teenagers have used Emoji in their text messages for many years, but Emoji’s use in the US (particularly on the iPhone) has gotten traction. It’s interesting that these symbols allow you to express more complex thoughts and emotions, however the nuances around them have not been standardized, between people and definitely between cultures. If I was a linguist, I would be fascinated by their adoption and use, as it’s a quickly evolving written language of its own.
Some interesting links:
Buy the book, Emoji Dick, which is Melville’s classic book translated to Emoji symbols.