This paper is concerned with the problem of mining competitors from the Web automatically. Nowadays, the fierce competition in the market necessitates every company to know not only which companies are its primary competitors but also in which domains the company's rivals compete with itself and what its competitors' strength is in a specific competitive domain. The task of competitor mining that we address in the paper includes mining all the information such as competitors, competing domains, and competitors' strength. A novel algorithm called CoMiner is proposed, which tries to conduct a Web-scale mining in a domainindependent manner. The CoMiner algorithm consists of three parts: 1) given an input entity, extracting a set of comparative candidates and then ranking them according to comparability, 2) extracting the domains in which the given entity and its competitors play against each other, and 3) identifying and summarizing the competitive evidence that details the...