1. A method comprising: selecting one or more additional queries related to an instance of an initial query; determining anonymized historical performance in terms of user interaction with each of one or more respective content blocks for the one or more additional queries, wherein a content block for an additional query includes the additional query and one or more content items for the additional query; determining that one or more filter criteria associated with the anonymized historical performance of a content block for particular additional query does not satisfy a threshold; in response to determining that one or more filter criteria associated with the anonymized historical performance of a content block for the particular additional query does not satisfy a threshold, filtering out the particular additional query from consideration for presentation at a next receipt of the initial query; receiving a second instance of the initial query; and providing one or more additional queries having anonymized historical performance that satisfy the filter criteria, one or more respective content blocks associated with the one or more additional queries, and search results associated with the second instance of the initial query.