Sentiment analysis involves the evaluation and classification of words based on their context, meaning, and emotional implications. Typically, if we were to look up a word in a dictionary we will find a meaning or definition for the word but, taken out of the context of a sentence, we may not be able to ascribe detailed and precise meaning to the word.
For example, the word toast could be defined as simply a slice of heated and browned bread. But in the context of the sentence He's toast!, the meaning changes completely. Sentiment analysis seeks to derive meanings of words based on their context and usage.
It is important to note that advanced sentiment analysis will expand beyond simple positive or negative classification and ascribe detailed emotional meaning to words. It is far simpler to classify words as positive or negative but far more useful to classify them as happy, furious, indifferent, or anxious.
This type of analysis falls into the category of effective computing...