1. A device comprising: a first component, implemented at least partially in hardware, to identify documents, where a first document of the documents is linked by a second document of the documents and the second document is one of a plurality of documents in an affiliated set of documents; and a second component, implemented at least partially in hardware, to: calculate a first value for each document in the affiliated set of documents based on a ranking score of the document and a number of outbound links from the document; determine a value of a degree of affiliation for the plurality of documents, where the value of the degree of affiliation indicates whether the plurality of documents in the affiliated set of documents are weakly affiliated or strongly affiliated; calculate a second value derived in part from the value of the degree of affiliation and a summation of the first values for the plurality of documents in the affiliated set of documents when the affiliated set of documents are weakly affiliated; calculate the second value as a maximum of the first values for the plurality of documents in the affiliated set of documents when the affiliated set of documents are strongly affiliated; assign a ranking score to the first document based the second value; and store the ranking score.