This document summarizes a presentation on opinion mining and sentiment analysis from user reviews and comments on the web. It discusses the basics of opinion mining, including defining the opinion model and levels of sentiment analysis. It outlines the requirements and design for a system to perform opinion mining, including functional requirements, architecture, and modules for opinion retrieval, composition, feature identification, and sentiment analysis. The design details the implementation of algorithms for identifying opinion words and orientation, as well as aggregating sentiments for features. Evaluation of the system examines effectiveness of feature identification and sentiment classification. Areas for future work are identified to improve handling of complex language patterns and domain-specific contexts.