1. A method, in a clustering search engine data processing system, for search disambiguation, the method comprising: receiving, from a requesting client of a requesting user, a search query, a bookmark data structure, and a viewed content history of the requesting user, wherein the viewed content history comprises at least a portion of a browser history maintained by the Web browser at the requesting client; performing a search to obtain a search result set comprising a plurality of data elements that satisfy the search query; classifying the search result set using the bookmark data structure to generate a clustered result set, wherein the clustered result set comprises the plurality of data elements clustered into a base taxonomy of categories and wherein the base taxonomy of categories is defined by the bookmark data structure; classifying, at the clustering search engine, the viewed content history of the requesting user into the base taxonomy of categories, wherein the base taxonomy of categories comprises a plurality of categories; and ranking, at the clustering search engine, the categories of the clustered result set according to the classification of the viewed content history to form a ranked cluster result set; and returning the raked clustered result set to the requesting client, wherein the bookmark data structure is maintained by a Web browser at the requesting client.