1. A method of determining a geographical relevance of a document, performed by one or more processors associated with one or more server devices, the method comprising: generating, using a processor associated with the one or more server devices, a plurality of histograms associated with a plurality of respective strings in the document by comparing strings in the document to a pre-existing plurality of strings for which histograms were previously generated, where the plurality of histograms relates occurrences of strings to geographical regions; generating, using a processor associated with the one or more server devices, a combined histogram for the document from the plurality of histograms by multiplying together values for each histogram of the plurality of histograms; and identifying, using a processor associated with the one or more server devices, a geographical relevance of the document based on the combined histogram.