15. A computer-implemented method of determining privacy-safe queries for providing to an advertiser, the method comprising: receiving a request for search query information based on at least one query keyword associated with an advertisement; identifying a first set of search queries from a search query log associated with the at least one query keyword, the set of search queries including search queries submitted to a search service over a predetermined length of time, wherein the search query log indicates that each query in the first set of search queries triggered at least one display of the advertisement that resulted in a user clicking on the advertisement; identifying a second set of search queries from the first set of search queries, the identifying including selecting search queries from the first set of search queries and for each selected search query: determining a number of unique identifiers associated with the selected search query, each unique identifier being associated with a unique client device that submitted a search request containing the search query; in response to determining that the number of unique identifiers exceeds a predetermined number of unique identifiers, including the selected search query in the second set of search queries, wherein the predetermined number of unique identifiers has a value greater than one and results in each search query included in the second set of search queries being specified as privacy-safe, and wherein each search query included in the second set of search queries does not include personal information; and associating the set of search queries with the advertisement and the at least one query keyword.
15. A computer-implemented method of determining privacy-safe queries for providing to an advertiser, the method comprising: receiving a request for search query information based on at least one query keyword associated with an advertisement; identifying a first set of search queries from a search query log associated with the at least one query keyword, the set of search queries including search queries submitted to a search service over a predetermined length of time, wherein the search query log indicates that each query in the first set of search queries triggered at least one display of the advertisement that resulted in a user clicking on the advertisement; identifying a second set of search queries from the first set of search queries, the identifying including selecting search queries from the first set of search queries and for each selected search query: determining a number of unique identifiers associated with the selected search query, each unique identifier being associated with a unique client device that submitted a search request containing the search query; in response to determining that the number of unique identifiers exceeds a predetermined number of unique identifiers, including the selected search query in the second set of search queries, wherein the predetermined number of unique identifiers has a value greater than one and results in each search query included in the second set of search queries being specified as privacy-safe, and wherein each search query included in the second set of search queries does not include personal information; and associating the set of search queries with the advertisement and the at least one query keyword. 18. The method of claim 15 wherein the association between the search queries from the search query log and the at least one query keyword comprises a broad match.