An algorithm that ranks web pages by the links between them.
PageRank is a popularity contest for web pages. A nod from the trusted kid beats ten random high-fives.
It helped early search engines rank pages. It also helps find important spots in a graph.
IR
PageRank was a key early tool for search ranking.
Graph Search
PageRank treats web links as a graph and moves importance along links.
BM25
BM25 checks keyword matches, and PageRank adds link authority.