Sentiment Analysis

What is Sentiment Analysis?
Consulting the all-mighty wikipedia (
you'll find that:

"Generally speaking, sentiment analysis aims to determine the attitude of a speaker 
or a writer with respect to some topic or the overall contextual polarity of a document"

Sentiment analysis, also referred to as Opinion Mining, implies extracting opinions, 
emotions and sentiments in text. As you can imagine, one of the most common 
applications of sentiment analysis is to track attitudes and feelings on the web, 
especially for tacking products, services, brands or even people. The main idea is
to determine whether they are viewed positively or negatively by a given audience.

Sentiment Analysis with R
I'm going to discuss three ways for performing sentiment analysis:

Following Breen's Approach

Using the R package sentiment

For more information check:
Introductory slides How Sentiment Analysis Works by Marie-Claire Jenkins