25. A system comprising: one or more computers, the one or more computers implementing: a dataset tool to identify each vector v in a dataset as a comparison vector, and a set of candidate vectors corresponding to each vector v; a similarity tool to determine, for each candidate vector w in each set of candidate vectors corresponding to v, a similarity estimate between the comparison vector v and the candidate vector w, and a similarity score between the comparison vector v and the candidate vector w if the similarity estimate meets a similarity threshold; and a results tool to include each pair of vectors comprising each comparison vector v and each respective candidate vector w in a list of similar pairs of vectors if the respective similarity score between the comparison vector v and the candidate vector w meets the similarity threshold.
69. The method of claim 25 , in which each vector represents a corresponding query, and each feature of each vector represents a relevance of a corresponding document to the query.