CO-CLICK BASED SIMILARITY SCORE OF QUERIES AND KEYWORDS

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for determining similarities between queries. A first query and a second query are identified, and first related queries associated with the first query and second related queries associated with the second query are also identified. One or more first features for the first query are identified, and one or more second features for the second query are also identified. A first score is calculated for each first feature based on the relatedness weight associated with the respective first related query including the term of the respective first feature, and a second score is calculated for each second feature based on the relatedness weight associated with the respective second related query including the term of the respective second feature. A similarity of the first query and the second query is determined based on the first score and the second score.