1. One or more computer-readable storage media comprising computer-program instructions that, when executed, cause one or more processors to perform acts comprising: determining a number of links on a source site that point to a destination site; calculating a first weight of an anchor text on the source site that links to the destination site based at least in part on the determined number of links, wherein the first weight of the anchor text is relatively higher when it is determined that the source site has a relatively fewer number of links that point from the source site to the destination site and the first weight of the anchor text is relatively lower when it is determined that the source site has a relatively larger number of links that point from the source site to the destination site; determining a number duplicated links between the source site and multiple other source sites that also link to the destination site; determining a number of unique links between the source site and the multiple other source sites that also link to the destination site; calculating a second weight of the anchor text based at least in part on the determined number of duplicated links and the determined number of unique links; calculating a final weight of the anchor text based at least in part on the first and second weights; and storing the final weight of the anchor text in association with the anchor text.