Ranking Content Using Content And Content Authors

Methods, systems, and apparatus, including computer program products for identifying original content. In one aspect a method is described that includes identifying a first document in a collection of documents. The first document contains a content piece and the content piece does not occur in any earlier document in the collection. The first document is associated with a first author and the first author associated with a first rank. The first rank of the first author is determined using a score of the content piece. The score is a figure of merit of the content piece.