22. A computer program product having a computer-readable storage medium having computer-executable code for constructing a domain-specific sentiment classifier for classifying sentiment expressed by documents in a specified domain, the computer-executable code comprising: a scoring module configured to score sentiments expressed by a plurality of domain-specific documents, the scoring module configured to score by performing steps comprising: determining that one or more of the domain-specific documents include an n-gram, calculating a score for the n-gram included in the one or more domain-specific documents, and calculating a sentiment score for the one or more domain-specific documents based on the score for the n-gram included in the documents; a lexicon module configured to create a domain-specific sentiment lexicon based at least in part on said scoring sentiments expressed by one or more domain-specific documents; a classifier module configured to generate the domain-specific sentiment classifier based on the domain-specific sentiment lexicon; and a storing module configured to store the domain-specific sentiment classifier.
22. A computer program product having a computer-readable storage medium having computer-executable code for constructing a domain-specific sentiment classifier for classifying sentiment expressed by documents in a specified domain, the computer-executable code comprising: a scoring module configured to score sentiments expressed by a plurality of domain-specific documents, the scoring module configured to score by performing steps comprising: determining that one or more of the domain-specific documents include an n-gram, calculating a score for the n-gram included in the one or more domain-specific documents, and calculating a sentiment score for the one or more domain-specific documents based on the score for the n-gram included in the documents; a lexicon module configured to create a domain-specific sentiment lexicon based at least in part on said scoring sentiments expressed by one or more domain-specific documents; a classifier module configured to generate the domain-specific sentiment classifier based on the domain-specific sentiment lexicon; and a storing module configured to store the domain-specific sentiment classifier. 26. The computer program product of claim 22 , wherein the classifier module is further configured to: build a model having n-grams of the domain-specific sentiment lexicon as features; and train the model on a training corpus having a set of high-sentiment documents.