35. A method, performed by one or more server devices, of determining the freshness of a first document, comprising: identifying, by a processor of the one or more server devices, a set of second documents that each contains, or once contained, a link to the first document; determining, by a processor of the one or more server devices, times at which each of the links to the first document existed; assigning, by a processor of the one or more server devices, a freshness score to the first document based on the determined times; and ranking, by a processor of the one or more server devices, the first document with respect to at least one other document based on the freshness score assigned to the first document.
35. A method, performed by one or more server devices, of determining the freshness of a first document, comprising: identifying, by a processor of the one or more server devices, a set of second documents that each contains, or once contained, a link to the first document; determining, by a processor of the one or more server devices, times at which each of the links to the first document existed; assigning, by a processor of the one or more server devices, a freshness score to the first document based on the determined times; and ranking, by a processor of the one or more server devices, the first document with respect to at least one other document based on the freshness score assigned to the first document. 36. The method of claim 35 , where assigning a freshness score to the first document further comprises: assigning a first freshness score to the first document if a first number of links that currently point to the first document is smaller than a second number of links that pointed to the first document at some time in the past.