Issue and challenges of online user generated reviews across social media and e-commerce website

At with the rapid development of web 2.0, large volume of freely opinion available on the different website, micro blogs, forum, newspaper, article, blogs etc. These opinions are very useful for individual, companies, product vendors and organization to making a crucial decision before buying any product or making the decision before manufacturing of any product and domain. However the individual, entity and product vendor uses the feedback of customer to predict the future sales performance and decision by evaluating the opinion and polarity. By comparison different features of product and different domain, companies, product vendors focus on improving the feature of product that is not popular. Here, we have describes various issue and challenges of opinion mining and sentiment analysis which affect result of opinion mining.