1. A computer-implemented ranking method comprising: sending, to a remote computer system via a network, a search query containing query terms; obtaining, at the remote computer system, documents resulting from performing the search query on a document database, the documents containing terms that match the search query; determining base relevancy scores for the documents; adjusting the base relevancy scores by applying a lead boosting value calculated according to an influence function, the influence function promoting a particular word position in a document, the particular word position being a predetermined number of words from the beginning of the document; and ranking the documents according to the adjusted base relevancy scores.