PREVENTING THE DISTRIBUTION OF FORBIDDEN NETWORK CONTENT USING AUTOMATIC VARIANT DETECTION

The subject matter of this specification generally relates to preventing the distribution of forbidden network content. In one aspect, a system includes a front-end server that receives content for distribution over a data communication network. The back-end server identifies, in the query log, a set of received queries for which a given forbidden term was used to identify a search result in response to the received query even though the given forbidden term was not included in queries included in the set of received queries. The back-end server classifies, as variants of the given forbidden term, a term from one or more queries in the set of received queries that caused a search engine to use the given forbidden term to identify one or more search results in response to the one or more queries and prevents distribution of content that includes a variant.