Re: Sadly we do need this
@dave – Bazinga! Sentiment detectors like Lymbix and others comb through communications for sentiment and tone. Of all the emotions, detecting sarcasm is particularly difficult, since it requires a great deal of context about the writer's subject, as well as an understanding of the use of language and paralanguage (images, etc). But, it can be done, and has been the subject of considerable work in computer labs since the 1970s.
It buys you the same thing that understanding any other emotional state. Emoticons are among the many ways people indicate sarcasm. Watch out for those winking ;-) faces . So, for the foreseeable future, the more textual communication we have, in social media and email, the more we need to understand what it all means in a context that makes sense. Challenging.
So, maybe not so sadly, we do need this.