10. A method performed by one or more server devices for ranking search results, the method comprising: referencing data from one or more user queries, wherein the data comprises one or more of general search engine results and vertical search engine results; generating a training set, wherein the training set comprises one or more search results extracted from the data; associating one or more click-based judgments with each of the one or more search results in the training set, wherein associating one or more click-based judgments with each of the one or more search results in the training set comprises: (1) determining that a plurality user queries are tail queries, wherein a tail query satisfies a threshold for the data referenced from one or more user queries; (2) aggregating the search results of plurality of tail queries into one or more classes of tail queries, such that the training set comprises at least one class of tail queries having a plurality of tail queries; and (3) associating one or more click-based judgments with each of the one or more classes of tail queries in the training set; determining one or more identifiable features from the training set based on the associated one or more click-based judgments; and based on determining one or more identifiable features from the training set, generating a rule set for ranking search results.
10. A method performed by one or more server devices for ranking search results, the method comprising: referencing data from one or more user queries, wherein the data comprises one or more of general search engine results and vertical search engine results; generating a training set, wherein the training set comprises one or more search results extracted from the data; associating one or more click-based judgments with each of the one or more search results in the training set, wherein associating one or more click-based judgments with each of the one or more search results in the training set comprises: (1) determining that a plurality user queries are tail queries, wherein a tail query satisfies a threshold for the data referenced from one or more user queries; (2) aggregating the search results of plurality of tail queries into one or more classes of tail queries, such that the training set comprises at least one class of tail queries having a plurality of tail queries; and (3) associating one or more click-based judgments with each of the one or more classes of tail queries in the training set; determining one or more identifiable features from the training set based on the associated one or more click-based judgments; and based on determining one or more identifiable features from the training set, generating a rule set for ranking search results. 13. The method of claim 10 , wherein the one or more identifiable features comprise at least one of clicks on only textual search results, clicks on vertical search results, clicks on captions and URLs of query-URL pairs, query classification confidence, vertical query confidence, overall clicks on the entire webpage, clicks on advertisements, and clicks on links to see the next page of results.