Patent ID: 8280881

Claim:
A computer-implemented method performed by a data processing apparatus, the method comprising: generating, for each of a plurality of search queries, a selection vector for the search query, each selection vector including a plurality of vector elements, each vector element corresponding to a unique image, and the value of each vector element being proportional to a number of selections of its corresponding unique image in response to the unique image being presented as a search result for the search query; selecting a first search query and a second search query from the plurality of search queries; generating an inverted image list for each of the unique images, the inverted image list including, for each unique image, one or more tuples, each tuple identifying a search query and including a non-zero vector element corresponding to the unique image and the search query; selecting, for the first search query, each inverted image list that includes a tuple identifying the first search query; selecting, for the second search query and from the selected inverted image lists that include the tuple identifying the first search query, each tuple identifying the second search query; and determining, from the selection vectors for the first and second search queries, a similarity measure that is a measurement of the similarity of the first search query to the second search query.