  Sentiment analysis (or opinion mining) on Twitter data has attracted much
attention recently. One of the system's key features, is the immediacy in
communication with other users in an easy, user-friendly and fast way.
Consequently, people tend to express their feelings freely, which makes Twitter
an ideal source for accumulating a vast amount of opinions towards a wide
diversity of topics. This amount of information offers huge potential and can
be harnessed to receive the sentiment tendency towards these topics. However,
since none can invest an infinite amount of time to read through these tweets,
an automated decision making approach is necessary. Nevertheless, most existing
solutions are limited in centralized environments only. Thus, they can only
process at most a few thousand tweets. Such a sample, is not representative to
define the sentiment polarity towards a topic due to the massive number of
tweets published daily. In this paper, we go one step further and develop a
novel method for sentiment learning in the MapReduce framework. Our algorithm
exploits the hashtags and emoticons inside a tweet, as sentiment labels, and
proceeds to a classification procedure of diverse sentiment types in a parallel
and distributed manner. Moreover, we utilize Bloom filters to compact the
storage size of intermediate data and boost the performance of our algorithm.
Through an extensive experimental evaluation, we prove that our solution is
efficient, robust and scalable and confirm the quality of our sentiment
identification.
