All Blogs Are Not Made Equal: Exploring Genre Differences in Sentiment Tagging of Blogs

One of the essential characteristics of blogs is their subjectivity, which makes blogs a particularly interesting domain for research on automatic sentiment determination. In this paper, we explore the properties of two most common subgenres of blogs – personal diaries and “notebooks” – and the effects that these properties have on performance of an automatic sentiment annotation system, which we developed for binary (positive vs. negative) and ternary (positive vs. negative vs. neutral) classification of sentiment at the sentence level. We also investigate the differential effect of inclusion of negations and other valence shifters on the performance of our system on these two subgenres of blogs.