12. The computer program product of claim 8 wherein each candidate phrase corresponds to a search query, and wherein the computer program instructions are further configured to enable the at least one computing device to reformulate a first one of the candidate phrases corresponding to a first search query as a rewritten search query where the first candidate phrase is found to be a superphrase of one or more of the seed phrases.
8. A computer program product for identifying superphrases in a set of candidate phrases with reference to a set of seed phrases, each of the candidate phrases comprising one or more candidate phrase words, and each of the seed phrases comprising one or more seed phrase words, the computer program product comprising at least one computer-readable medium having computer program instructions stored therein configured to enable at least one computing device to: sort all distinct ones of the seed phrase words in the set of seed phrases; index each seed phrase in the set of seed phrases by sorting the corresponding seed phrase words, and indexing the seed phrase with reference to the sorted distinct seed phrase words; and determine whether each candidate phrase is a superphrase of one or more of the seed phrases by sorting only the corresponding candidate phrase words included among the distinct seed phrase words, and determining whether all of the seed phrase words of any of the indexed seed phrases are included among the sorted candidate phrase words, wherein the candidate phrase is a superphrase based on the determination that all the seed phrase words of any of the indexed seed phrases are included among the sorted candidate phrase words.