As the increasing use of web, number of users expressing their views about particular product, news, individual or organization also increased. Users tend to write reviews when it make a purchase on web. These reviews are extremely helpful for both, the other users who are intending to make a purchase and the related company to who wants to get feedback and suggestion about the product. User reviews contains information about product features, user expression and sentiments of users regarding the product. As huge number of reviews and dimensionality is present in these reviews, it may create conflict in purchase decision. Thus, more improved technique to catch user's precise sentiments towards the product is evolved i. e. opinion mining which comprises opinion target and opinion words extraction. Many methods have evolved for opinion mining and extraction.

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Opinion Mining Opinion Target Opinion Word Reputation System