Topical Relevance

With search engines, topical relevance is mainly used in conjunction with backlinks (incoming links).

Websites that carry similar content are said to have topical relevance. Backlinks from websites that are topically relevant have more impact on a website’s position in search results than backlinks from sites that are not related. Search engines assume that topically relevant links are used to offer users additional information that could be helpful. With unrelated links there is a high probability that they have been paid for or included for the purpose of improving a site’s position in search results.