Mining opinions about products in the business domain has been getting a lot of attention now days, and therefore benefiting both businesses as well as customers. The opinions expressed by the users or customers on products making use of multiple platforms of social media and e-commerce sites can help the potential customers to determine which product is good for them or not and at the same time helping the businesses to determine the costumer's views about their products. The mobile phones is a type of product type which is high in demand in current times and people are very much interested in knowing about the reviews of others before buying mobile phones. This book describes the development of a system for mining the reviews about mobile phones using GATE framework.