Social network search engines are a class of search engines that use social networks to organize, prioritize or filter search results. There are two subclasses of social network search engines: those that useexplicit social networks and those that use implicit social networks.

Lacking trustworthy explicit information about such viewpoints, this type of social network search engine mines the web to infer the topology of online social networks. For example, the NewsTrove search engine infers social networks from content - sites, blogs, pods and feeds - by examining, among other things, subject matter, link relationships and grammatical features to infer social networks.