The below slider contains links to as well as brief explanations and ratings of free data sources. A data source gets a high ranking if it is easy to access and contains unique and/or comprehensive information for the specific business context. More slides will be added periodically, with a goal of 5 slides by 2013. 

Sentiment Data
While all of the below sources are free, some authors may restrict use by for-profit companies. Please pay attention to licensing statements.
Wilson, Wiebe, and Hoffmann (2005): list of 8,000+ words with 5-point polarity scale
P.J. Stone et al, Harvard University: Over 26 categories of words (data link)
Alex Davies: list of 5400+ tweeted words with happy/sad log probabilities
WordNet, Princeton University: comprehensive lexical database with different meanings for words based on the context (software download too)
Bo Pang, et al, Cornell University: collection of polarity, sentiment, and subjectivity data sets, as well as papers by these pioneering authors
Scrapmaker: several lists of words, including neg/pos (no scale ) & stop words
Bing Lui et al, University of Illinois at Chicago: collection of data sets, including opinion (6800+ words, negative or positive) and various review data
Coming Soon…

Data Feeds

U.S. Demographic and Economic

Company Information

Social Networks

Financial Information