Simple Sentiment Analysis
bayesian, nlp
Solution
A Bayesian classifier with a bag of words representation is the simplest statistical method. You can get significantly better results by moving to more advanced classifiers and feature representation, at the cost of more complexity.
Statistical methods aren't the only game in town. Rule based methods that have more understanding of the structure of the text are the other main option. From what I have seen, these don't actually perform as well as statistical methods.
I recommend Manning and Schütze's Foundations of Statistical Natural Language Processing chapter 16, Text Categorization.
Problem
It appears that the simplest, naivest way to do basic sentiment analysis is with a Bayesian classifier (confirmed by what I'm finding here on SO). Any counter-arguments or other suggestions?