Abstract. The web with its rapid expansion has become an excellent resource for gathering information and people’s opinion. A company owner wants to know who is the competitor, and a customer also wants to know which company provides similar product or service to what he/she is in want of. This paper proposes an approach based on mutual information, which focuses on mining competitors of the entity(such as company, product, person ) from the web. The proposed techniques first extract a set of candidates of the input entity, and then rank them according to the comparability, and finally find and organize the reviews related to both original entity and its competitors. A novel system called ”CoDis” based upon these techniques is implemented, which is able to automate the tedious process in a domain-independent and web-scale dynamical manner. In the experiment we use 32 different entities distributed in varied domains as inputs and the CoDis discovers 143 competitors. The experi...