32. A system, implemented within one or more computer devices, for determining a freshness of a first document, comprising: means for identifying a set of second documents that each contains, or previously contained, a link to the first document; means for determining a freshness attribute associated with each document of the set of second documents; means for determining a freshness score of the first document based on the freshness attribute associated with each document of the set of second documents, where the freshness attribute indicates when each document was last modified; and means for ranking the first document with respect to at least one other document based on the determined freshness score.
32. A system, implemented within one or more computer devices, for determining a freshness of a first document, comprising: means for identifying a set of second documents that each contains, or previously contained, a link to the first document; means for determining a freshness attribute associated with each document of the set of second documents; means for determining a freshness score of the first document based on the freshness attribute associated with each document of the set of second documents, where the freshness attribute indicates when each document was last modified; and means for ranking the first document with respect to at least one other document based on the determined freshness score. 34. The system of claim 32 , further comprising: means for assigning a first freshness score to the first document if a majority of documents of the set of second documents correspond to documents that have freshness values that are less than a threshold; and means for assigning a second freshness score to the first document if a majority of documents of the set of second documents correspond to documents that have freshness values that are greater than or equal to the threshold, where the first freshness score is less than the second freshness score.