13. A computer readable medium having stored thereon one or more sequences of instructions for causing one or more microprocessors to perform the steps for delivery of content from a corpus of data, the steps comprising: receiving a search query; generating a search query result set by searching a corpus of data for items that satisfy the search query; identifying a trigger query, said trigger query associated with a content presentation action; generating a trigger query result set by searching the corpus of data for items that satisfy the trigger query; determining a level of intersection between the search query result set and the trigger query result; and presenting content as specified by the content presentation action when said level of intersection is greater than a predetermined threshold.
13. A computer readable medium having stored thereon one or more sequences of instructions for causing one or more microprocessors to perform the steps for delivery of content from a corpus of data, the steps comprising: receiving a search query; generating a search query result set by searching a corpus of data for items that satisfy the search query; identifying a trigger query, said trigger query associated with a content presentation action; generating a trigger query result set by searching the corpus of data for items that satisfy the trigger query; determining a level of intersection between the search query result set and the trigger query result; and presenting content as specified by the content presentation action when said level of intersection is greater than a predetermined threshold. 15. The medium according to claim 13 , wherein said level of intersection is determined by dividing the number of items in the intersection of the search query results and the trigger query results sets by the number of items in the search query result set.