6. A computer-readable physical storage medium that stores instructions executable by at least one processing device, comprising: instructions that, when executed, cause the processing device to: receive a first set of identification information identifying one two or more input documents for which a first generation relatedness score is sought; use said first set of identification information to access a stored computer-accessible index to produce a second set of identification information identifying one or more citationally related documents, said one or more citationally related documents being citationally related to said at least two or more input documents at a first or higher generation citational relationship; assigning a first generation relatedness score to said two or more input documents, said first generation relatedness score being calculated at least in part by counting a number of shared citational relationships occurring between said two or more input documents and said one or more citationally related documents at second generations or higher, said first generation relatedness score being statistically calculated to indicate whether a first generation citational relationship exists between said two or more input documents, wherein first generational relationships exist between documents when a first document directly cites to a second document, wherein second generational or higher relationships exist between the first document and a third documents when the first document cites to one or more intervening documents that cite to the third document; and output the first generation relatedness score between said two or more input documents.
6. A computer-readable physical storage medium that stores instructions executable by at least one processing device, comprising: instructions that, when executed, cause the processing device to: receive a first set of identification information identifying one two or more input documents for which a first generation relatedness score is sought; use said first set of identification information to access a stored computer-accessible index to produce a second set of identification information identifying one or more citationally related documents, said one or more citationally related documents being citationally related to said at least two or more input documents at a first or higher generation citational relationship; assigning a first generation relatedness score to said two or more input documents, said first generation relatedness score being calculated at least in part by counting a number of shared citational relationships occurring between said two or more input documents and said one or more citationally related documents at second generations or higher, said first generation relatedness score being statistically calculated to indicate whether a first generation citational relationship exists between said two or more input documents, wherein first generational relationships exist between documents when a first document directly cites to a second document, wherein second generational or higher relationships exist between the first document and a third documents when the first document cites to one or more intervening documents that cite to the third document; and output the first generation relatedness score between said two or more input documents. 10. The computer-readable physical storage medium of claim 6 , wherein said instructions, when executed additionally cause the processing device to output on a printer module said first generation relatedness score of said two or more input documents.