1. A computer-implemented method, comprising: receiving data in a memory of a computer, wherein the data includes one or more terms; accessing, with the computer, a database of sponsored content, wherein each item of sponsored content in the database is associated with one or more phrases, wherein the phrases are used to access the sponsored content; determining, with a processor of the computer that accesses the data in the memory, whether any of the terms is ambiguous such that the term, when combined with different other terms, produces different phrases which access substantially different sets of items of sponsored content in the database including identifying a first phrase that is a combination of an ambiguous term and one or more terms of the different other terms and identifying a second phrase that is a combination of the ambiguous term and one or more other terms of the different other terms wherein the first phrase and the second phrase access different sets of items of the sponsored content wherein determining a term is ambiguous includes identifying a plurality of phrases that contain or are related to the term; for each pair of phrases, determining a measure of similarity including determining a number of co-occurrences of the pair of phrases in a set of documents and a number of single occurrences of a phrase in the pair of phrases in the documents; determining that the pair of phrases are similar when the measure of similarity is above a threshold; and determining a term is ambiguous when two or more phrases of the plurality of phrases are dissimilar; for an ambiguous term, replacing the term in the data in the memory wherein replacing the term comprises replacing the term by selecting either the first or the second phrase both of which include the ambiguous term; and selecting, from the database, sponsored content using the selected one of either the first or the second phrase.
6. The computer-implemented method of claim 1 , wherein replacing comprises removing the ambiguous term from the one or more terms.