13. The computer-implemented method of claim 12 , wherein determining the usage score from the frequency of visit value and the unique visit value for the site comprises: determining a frequency of visit score based on a log ratio of the frequency of visit value to a maximum frequency of visit value; determining the unique user score based on a ratio of the unique visit value to a maximum unique visit value; and determining the usage score from the frequency of visit score and the unique user score.
12. A computer-implemented method comprising: identifying at a server a plurality of sites, each of the sites hosting a respective plurality of documents; wherein the plurality of sites include at least one site visited by multiple distinct counted visitors during a time period; accessing, at the server, usage information associated with each of the plurality of sites hosting the documents, the usage information including, for each site: (i) a frequency of visit value based on a total number of times the site was visited by all counted visitors visiting the documents hosting by the site during a time period; and (ii) a unique visit value based on a number of unique visitors among all counted visitors visiting the respective documents hosted by the site; determining at the server, for each site, a usage score from the frequency of visit value and the unique visit value for the site; and determining, at the server, an organization for the documents based on the usage scores for the respective sites hosting the documents.